Some observations on the predator-prey complex in the Gallatin valley
by Cecil P Haight
A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the
degree of Master of Science In Zoology
Montana State University
© Copyright by Cecil P Haight (1941)
Abstract:
Some observations of predator-prey relations were made on a section of land in the midst of first grade
irrigated farming land lying just west of the Montana State College campus. The study was carried out
between October 1, 1939 and April 1, 1941.
Scat and pellet analyses and field observations were made to try to establish some of the relations
between the raptores and predators and the prey species on the area.
Despite ample opportunity to prey on domestic animals all predation was on wild populations, mainly
on meadow mice. Insects were taken in significant quantities when they were available. All the
predators ate a considerable amount of carrion in the winter. Predators on this area had no detrimental
effect on normal prey populations. SOME OBSERVATIONS ON THB PREDATOR-PREY COMPLEX
IN THE GALLATIN VALIEY
by
CECIL P. HAJGHT
A THESIS
Submitted to th e Graduate Committee
in
p a r t i a l fu lf illm e n t of th e requirem ents
f o r .th e degree o f
M aster o f Science in Zoology
at
Montana S ta te College
Approved*
Bozeman, Montana
June, 1937
f(37S
-
2-
IABUD OF CONTENTS
L is t o f Tables and P la te s
A b stra ct
• • •
In tro d u ctio n
.................
. . . . . .
A Development o f Ideas
Page
5
li.
5
•
5
D escrip tio n o f Area . . .
10
Techniques Employed in th e Study
13
The Fauna ................................................. ............................................
I)
The B iologival Complex
l£
. . . . . . . . . . . . . . . . . . . .
Weather and Animal Movements
F lora-fauna re la tio n s h ip s .
P redation P a tte rn s . . . . .
Mice . . . . . . . . .
Ground S q u irre ls • . •
Coyote . . . . . . . .
Skunk . . . . . . . . .
P a rtrid g e s .....................
Hawks . . . . . . . . .
Owl . . . . . . . . . .
Magpies . . . . . . . .
General • .........................
16
20
23
23
25
25
28
28
29
32
32
32
Summary and Conclusions
37
L ite ra tu re C ited and Consulted
38
Appendix
bl
-3
LIST OP IABIES AND PLATES
Table
I Numbers o f principal prey sp ecies on the area by season. • 15
II Seasonal summary o f coyote scat an alysis . . . . . . . . . 2 7
II I Seasonal summary o f hank p e lle t analysis
IT Seasonal summary o f owl p e lle t an alysis
• • • • • • • • • 3 3
T Irregular food h a b its o f predators studied • • • • • •
••33
TI Summary o f weather conditions in the G allatin V alley
during the period o f in v estig a tio n • • • • • • • • • •
IiO
VII Tabulation o f coyote so at analyses • • • • • • • • • • • • I j B
VIII Tabulation o f hawk p e lle t analyses • • • • • • • •
IX Tabulation o f owl p e lle t analyses
. . • •5 °
• • • • • • • •
••••5U
Z Tabulation o f skunk and weasel scat analyses • • • • • • •
P late
I Cover map of study area
. . . . . . . . . . . . . . .
..Iil
II Graphic suggestion o f predator-pressure and
p r e y -a v a ila b ility • • • .............................
I I I Typical coyote scat
• • • • • • •
••
Sample data sheets used in the f ie ld
Ii2
• . . . . . .
TV Typical hawk and owl p e lle ts . . . . . . .
56
••
. . . . . .
. . . . . ••-'• • • • •
. Iili
. . Ii6
• • • .57
ABSTRACT
Some observations of p red a to r-p re y r e la tio n s were made on a se c tio n
o f land in th e m idst of f i r s t grade i r r ig a te d farming land ly in g j u s t
w est o f th e Montana S ta te College campus.
The study was c a rrie d out
between Ootober I , 1939 and A p ril I , IgttI e
Scat and p e lle t analyses and f i e l d observations were made to t r y to
e s ta b lis h some o f the r e la tio n s between th e ra p t ores and p red a to rs a™*
th e prey sp ecies on the a re a .
D espite ample o p p ortunity to prey on domestic anim als a l l preda­
tio n was on w ild p o p u latio n s, m ainly on meadow m ice.
In se c ts were
tak en in s ig n if ic a n t q u a n titie s when th ey w ere a v a ila b le .
A ll th e
p red a to rs a te a considerable amount o f c a rrio n i n th e w in te r.
P redators
on t h i s a re a had no d e trim e n tal e f f e c t on normal prey p o p u la tio n s.
-5 INTEODUCTION
The study o f p red a tio n i s a r e la tiv e ly new aspect of animal ecology.
Few workers have in vestigated, t h is f i e l d in d e ta il , hence any concrete
evidence o ffe re d in in te r p r e ta tio n of p red a to r-p re y re la tio n s i s valuable
in h elp in g to complete th e p ic tu r e .
A survey of l i t e r a t u r e re v e a ls the need of accurate d a ta on lo c a l
p red a tio n p a tte rn s and the atten d a n t c o lle c tio n of h a b it v a ria tio n in
d iffe re n t a re a s.
This p ro je c t was undertaken in order to g ath er d a ta
which would f i l l in p a rt of another gap in t h i s f i e l d .
a
SE m cpm r
of ideas
E arly in th e Middle Ages w ritte n records were made o f th e d e s tru c tiv e ­
ness of "vermin" to small game and domestic anim als.
These p red a to rs were
hunted unceasingly and no sportsm an's code was invoked a g ain st th e manner of
t h e i r cap tu re.
The a n cien t thought th a t p red a to rs a re "vermin" to be
exterm inated bore the im p lica tio n th a t any carnivore (pred ato r) tak in g an
animal which man wanted f o r h im self was a t h i e f and should be punished
accordingly.
The id e a p e r s i s t s in th e minds o f many even today.
However, people in g en eral, and n a tu r a li s t s in p a r tic u la r , a re
beginning to r e a liz e the in c a lc u lc a b le value of pred ato ry sp ecies.
The
re la tio n s h ip s of p re d a to r and prey sp e cie s, the in te r r e la tio n s of p red a to rs—
th e contemporary concept of p red atio n —i s y e t immature; the e a r l ie s t
in te n siv e study of th ese in te r r e la tio n s was begun l i t t l e more than a decade
ago.
Several p io n eers in the study of p re d a tio n were McAtee, Stoddard,
Leopold, and E rrin g to n .
These, and o th e rs, have se t f o rth concisely
v ario u s phases o f the p red a tio n theory which e a r l ie r were not understood or
-6 -
were unknown*
Many people do not r e a liz e Wiat far reaching e ffe c ts may r e su lt from
some seemingly minor disturbance in the b iota o f an area*
Breticenridge
(1958) suggests th at most hunters advocating predator control "do not
seem to appreciate what tremendously complex and powerful natural forces
they are opposing in trying to bring about an unnatural, Utopian situ a tio n
where game i s continuously abundant* • • They do not stop to figure out
that i f they k i l l o f f a l l the hawks and owls th at prey to some extent on
game sp e c ie s, they are a t the same time removing e ffe c tiv e and natural
checks on ground sq u ir re ls, m ice, rab b its and lik e forms thsfc in turn
destroy cover (and food) for game birds."
Leopold (1933) quotes McLean as saying, "There i s a growing tendency
on the part o f s c ie n tis ts to defend the predator as indispensable t o the
welfare of th e animal preyed upon."
Cahalane (1939)# reporting on research
done in Yellowstone National Park, Modoc Lava Beds, and Mt* McKinley
National Monuments, says, "Results of stu dies brought to conclusion ind icate
that control (o f coyotes) a t present i s not d esirab le.
Rather, on the
contraxy, coyotes under present circumstances are exercising a b e n e fic ia l
influence by removing diseased and crippled waterfowl and surplus prey
mammals*" These crippled and surplus animals would have to disappear
anyway, by m igration, starvation , d isea se , or death*
The eco lo g ical concept o f predation in so in f in it e ly variable th at
laws governing predator-prey r ela tio n s are d i f f i c u lt to formulate*
Even though d e fin ite ru les for interp retation may not y e t be made, certain
generalizations convenient for in terp retation o f data are in order*
-7 -
Leopold (1933) distinguished fiv e d iffe re n t types of predations
1)
2)
3)
h)
5)
A ccident—chanoe predation*
H abit—acquired t a s t e s t a r ti n g w ith a c c id e n ta l predation*
Education o r "sucker l i s t " —tak in g prey t i l l i t becomes too wary f o r
capture*
S ta rv a tio n —praying on v ictim s o f unfavorable environment*
S a n ita ry —c u llin g weak, d ise a s e d , o r dumb in d iv id u als*
A s ix th type o f predation, has been suggested, one which i s perhaps
very im portant in d ealin g w ith the e ffe c ts o f p red atio n on prey sp e c ie s,
th is i s psychological predation*
When a hawk so h a rr ie s a covey of q u a il
th a t th e y re fu s e to venture f a r enough from t h e i r s h e lte r to obtain, adequate
food, and when they do ven tu re even a sh o rt d istan c e away a magpie o r a
small song b ird swooping clo se w i l l send them back to co v er, th e n th e
psychological phase o f p red a tio n o ccu rs.
The damage i s no t d ir e c tly physi­
cal b u t i s in d ir e c tly so by w earing th e prey down through th e medium of
fear*
At tim es t h i s fa c to r may be most im portant in predation*
P redation includes n o t only c u llin g out u n f i t in d iv id u a ls , b u t also
a re g u la to ry a c tio n on th e movements and d is tr ib u tio n of th e p rey , thus
preventing s t a t i c and over-crowded populations*
Henderson and Craig (1932)
in tim ate t h i s in saying, "On our w estern p la in s and m ountains, coyotes,
wolves and other p red ato ry mammals had long liv e d in proxim ity to d e e r,
ra b b its and o th e r mammals, in such eq u ilib riu m as n e ith e r to exterm inate
them nor to perm it them to become overabundant •"
Leopold (1933) presents the r e la tiv e ly new concept that a ltern ative
foods fo r predators may a c t as "buffers" between game populations and
th e ir predators*
This bu ffer action r e su lts because of sheer numbers or
because o f greater a v a ila b ility .
rank*
Buffers are a ltern a tiv e foods o f stap le
E rrln g to n and Stoddard agree w ith Leopold in recognizing th e value
o f b u ffe r sp ecies and the trem endously complex and v a ria b le r e la tio n s o f
p red a to rs to b u ffe rs to game.
Not only may b u ffe rs be b e n e fic ia l to game,
th ey may a lso b rin g about co n d itio n s d e trim e n tal to them .
Cyclic behavior
o f b u ffe r species may, during p ro g re ssiv e p h ases, a ffo rd p ro te c tio n to game
sp ecies and during th e re g re s s iv e phases may throw an unusually heavy load
on th e game, th u s causing them much d i s t r e s s .
Five d e le te rio u s e ff e c ts which b u ffe rs may have on game species are
l i s t e d by Leopold (1953)I
1)
Uhea p re se n t i n co n ce n tra tio n th ey may a c t as b a i t f o r p redators not
norm ally in th e a re a .
2) They a r e in term ed iate h o sts o f d isease and p a ra s ite s of many o f th e
game sp e c ie s.
3) They throw a load on th e game sp ecies d uring the w in ter because o f
h ib e rn a tio n or u n a v a ila b ility through deep snow.
h) D iurnal b u ffe rs a re n o t a v a ila b le to nocturnal p red a to rs and v ic e versa
th u s th e "balance" o f populations i s changed from n ig h t to day.
5 ) B uffers may a c t in d ir e c t com petition w ith the game f o r food or may
become p red ato ry on t t e game i t s e l f .
B uffers a re c lo s e ly t i e d up w ith th e food h a b its of p re d a to rs.
Concerning apparent p re d ile c tio n s o f p red a to rs MoAtee (1932) a s s e r ts th a t
"W ithin s iz e l i m i t s , anim als of p r a c tic a lly every kind a o essib le to b ird s
a re preyed upon, and so a s we consider the records f o r group a f t e r group
a tendency f o r th e number o f cap tu res t o be in p ro p o rtio n to th e abundance
o f th e animal concerned i s unm istakable.
A v a ila b ility i s undoubtedly th e
c h ie f f a c to r involved in t h e choice of food, and p red atio n th e re fo re tends
" -'
.................................-
-
,
to be in p ro p o rtio n to p o p u la tio n ."
•
.....................................................................................................
. . . .
.............................
Hence, a s b u ffe r sp ecies a re u su a lly
p re se n t in la rg e numbers, th e y c o n s titu te a ra th e r la rg e p a rt o f th e d ie t
-9 -
o f predators*
E rrln g to n (1935) p re se n ts a m o d ificatio n o f IioAtee1s
p r in c ip le , “M aterial or heavy p red a tio n upon vigorous a d u lt w in te r bobw hites appeared la rg e ly confined to th a t p ro portion of th e popu latio n which
was in excess of the environment p ro p erly to accommodate." A combination
o f th ese two p ro p o sitio n s suggests th a t p red atio n tends to be i n p ro p o rtio n
to th e pop u latio n in excess of the normal carrying c ap acity o f th e range*
M ills (1937) b rin g s out th e f a c t th a t “inform ation now being
obtained by game management s p e c ia lis ts te n d s t o show t h a t p red a to rs have
b u t l i t t l e e ff e c t on normal populations of game sp e c ie s, and t h a t th e check
which predatory species ap p ly to th e in cre ase of th e s e valu ab le forms i s
n e g lig ib le *“ E rrin g to n (1936) s t a t e s , "The trimming down by p red a tio n o f
excess population t h a t must d isa p p ea r anyway, i s in c id e n ta l,"
Food h a b its , th e n , are determ ined by lo c a l c o n d itio n s, and vary as
much as th o se conditions*
Composite stu d ie s of p red a to r food h a b its a re
only a g en eral guide to lo c a l problems according to Leopold (1933)•
R esu lts o f lo c a l stu d ie s cannot be tra n s fe rre d from one l o c a l i t y t o another
w ith any ex p ec ta tio n of su ccess, b u t th ey a re in v alu ab le in completing th e
composite o f a re g io n a l food h ab its survey*
The exceedingly complex p a tte rn of p re d a tio n must be in te rp re te d w ith
c are.
Laboratory exam ination of p e lle ts and s c a ts a lo n e w ill n o t yfeld a
tr u e p ic tu re o f th e food h a b its o f a p re d a to r, nor w i l l f i e l d o bservation
by i t s e l f give a tr u e p ictu re*
Both sources o f d ata must be c a re fu lly
considered in r e l a ti o n to the m ultitudinous environm ental f a c to r s , each o f
which c o n trib u te s i t s share in making th e p red a to r-p re y p a tte rn of t h a t
p a r tic u la r lo c a lity j u s t what i t is*
-1 0 -
DESCRI FT ION CF THE ARM
This p a r tic u la r a re a was chosen because o f a c c e s s ib ility from th e
college*
During th e course o f the stu d y , October I , 1959 to March I , 1941,
many s h o r t t r i p s were made to i t a s w ell as a l l day observations*
The a re a under c o n sid era tio n i s one se c tio n (640 a c re s) ly in g a h a lf
m ile west o f th e Montana S ta te College campus (Sec* 14, T 2 S , R 5 E ,
Montana P rin c ip a l M eridian)* The s e c tio n i s lo ca te d in th e m idst o f the
i r r ig a te d farm ing s e c tio n o f th e upper G a lla tin Valley*
From t h i s p o in t
th e land slopes upward to th e mountains about s ix m iles d is ta n t to th e
south and east*
th e n o rth .
The a re a i s m oderately le v e l w ith a g e n tle d e c liv ity to
This se c tio n i s c la s s if i e d a s f i r s t grade ir r ig a te d farming
land w ith in te rsp e rse d tongues of fo u rth grade land running up th e seepage
sloughs and along some of th e d itc h e s . 1
In t h i s kind o f fanning d i s t r i c t
a l l p o ssib le land is under c u ltiv a tio n and com paratively l i t t l e headland
i s l e f t around th e f i e l d s ; f o r th e most p a r t clean farming is p racticed*
Four o p erato rs c o n tro l a q u a rte r of a s e c tio n each, thus d iv id inwg i t
-
into*
I)
-
. . . . . .
-
-
................................
................. _
. . . . . .
S ta te College experim ental p lo ts end p a s tu re , 2)
d a iry sto c k and sheep w ith small f i e l d s , end 3 )
end 4 )
.
p a stu re f o r
two d iv e rs ifie d
farm ing u n its * P a r tic u la r ly i n the l a t t e r th e p a stu re s and th e crop a re a s
a re w e ll d isp ersed among one a n o th e r so t h a t a maximum o f edge e ff e c t
re s u lts .
There are th re e main p a stu re a re a s on th e s e c tio n re s u ltin g
from lan d to o w et to c u ltiv a te e a s ily —few rth grade land—or from th e need
o f p astu re f o r d a iry stock*
1Land c la s s if ic a tio n maps, unpublished, Mont, A gric• Exp11 . S ta tio n i n
cooperation w ith th e Bureau o f Chem• end S o ils , Bozeman, Montana*
*11—
Along th e fence rows, la rg e i r r ig a ti o n d itc h e s , and along many o f th e
sloughs th e re a re sev eral la rg e tr e e s and a considerable amount o f b ru sh .
(See appended map, P la te I , f o r d e ta ils o f c o v er.)
The brushy cover
c o n sists mainly of various age c la ss e s of w illow (S ail= s p p .) , a ld e r
(AteMs eP*)» w ild rose (Rosa s p . ) , and snowberry (Svmphoricamos s p .)•
Around th e farm yards and s c a tte re d a lo ig the fen ces and d itc h es th e re a re
cottonwoods (Pgpulus a n g u s tifo lia ) and la rg e willow tr e e s (S a lix s p .) .
The g rass in th e p astu res i s m ainly blu e g rass (Poa s p .) , w ith some slough
g rass (J a m w s p .) , brome (Brcmus s p . ) , and sedges (SSCSZL sP*)•
"The clim ate of the G allatin V alley in general i s sim ilar to that o f
other intermountain v a lle y s o f the northwest.
I t i s continental in
character and is subject to wide extremes o f seasonal and d a ily tempera­
tu r e s, a d ifferen ce o f 36° F sometimes occurring w ith in 2^ hours.
Winds are
variable in both movement and d ir e c tio n , in the daytime the winds may be
p rev a ilin g ly from the west or southwest, and a t night they very often s h ift
to th e southeast.
the e a st.
Locally some of th e cold est winds in w inter are from
During th e winter warm "chinook" winds are also o f variable
occurrence. • • The mean annual temperature a t the agricu ltu re c o lleg e
a t Bozeman is U J *0 F. .
(DeYoung and Smith, 1931) .
The f a l l and e a rly w in te r of 1939 were extended and m ild alm ost to
an extreme. 1
There was no snow and r e l a ti v e ly l i t t l e m oisture u n t i l th e
l a s t week in December, during which time th e tem perature was moderate w ith
only occasional f re e z e s .
U n til th e f i r s t o f January, 1 9 U , th e w eather
See Table V. Summary o f w eather conditions in th e G a lla tin V alley
during th e perio d o f in v e s tig a tio n .
-
was open
bo
12-
th a t upland game b ird s , mice and ra b b its could o btain food
d ir e c tly from the ground and from very low v eg etatio n .
The f i r s t two months of 19*10 showed an unusually heavy snow fall.
When leav in g the road during January and February I t was necessary to
tra v e l on s k iis , and on sev eral occasions th e depth o f snow a t random
p o in ts on the a re a was determined to vary between lU inches and two f e e t,
w ith d r i f t s near brush rows fiv e fe e t or more in h e ig h t.
During th e time
th is heavy blanket of snow was on the ground none of the short v eg etatio n
o r p la n ts w ith p lia b le s ta lk s was a v a ila b le to ahim als liv in g above the
snow.
Because the f i r s t snows were heavy and f e l l on a r e la tiv e ly f r o s t fre e ground, th e warmth o f th e ground below drew the few inches of f r o s t
from the su rface leaving so ft ground under the snow throughout th e w in ter.
There was no snow on the ground a f t e r March 20 and p r a c tic a lly no free zin g
weather from th a t date on in to th e summer.
The sp rin g and summer were
average fo r the v a lle y w ith average monthly tem peratures from JSeF. in
March to S7*F. in August end average r a i n f a l l fo r th a t p erio d 1.67 inches
p e r month.
The v e g etatio n on th e se c tio n was heavy thus a ffo rd in g abundant
food and cover f o r game through the spring and summer.
September and October, 19Uo, were warm and damp.
The cover and food
p la n ts remained in good c o n d itio n and green u n t i l the middle o f the
follow ing month.
L i t t l e movement o f game and p re d a to rs occurred t i l l the
f i r s t o f November, 1940, since the weather and food conditions were id e a l
fo r f a l l .
The f i r s t snow f e l l during the f i r s t week of November and
w in ter weather s e t in immediately although fo r no len g th o f time was the
—13*
enow ex cessiv ely deep a s during the previous w inter*
W ith exception o f
one week in December th
e winter months o f ISUO-Iil might be considered mild*
,
.
.
.
The sp rin g was norm al, the snow having a l l m elted by mid-March and th e
v e g e ta tio n showing signs o f sp rin g growth almost immediately in the
warm days th a t follow ed.
F ie ld observations and c o lle c tio n of o th e r d a ta
were term in a ted March 31» 19^1*
TECHNIQUES EMPLOYED IN THE STUDY
Two main a tta c k s w ere made on th e problem—I )
th e f i e l d and 2)
a c tu a l o b serv atio n in
in te r p r e ta tio n o f sc a t and p e ll e t an aly sis*
Approximately
te n hours a week were sp en t in o b serv atio n on th e se c tio n w ith th e exception
o f th e summer o f I Slt-O when 6-8 hours were spent in th e f i e l d by an
inexperienced f i e l d worker*
System atic o bservation on th e se c tio n w ith
th e a id of f i e l d g la s s e s , in te r p r e ta tio n o f sig n , and c o lle c tio n of
specimens, s c a ts and p e ll e t s y ield ed a considerable amount of valuable
supplementary data#
Some f a c t s were obtained from th e farm ers on the
s e c tio n .
la b o ra to ry exam ination o f s c a ts and p e lle ts follow ed techniques used
•
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• -
~
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• -
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-
.
-
....... .
_
..
. . » *
. ... ..
by th e F ish and W ild life Service*
The item s were recorded by number
occurring in each s c a t o r p e lle t*
A q u a n tita tiv e measurement o f th e
amounts of each food item e a te n was n o t k e p t.
These d a ta were separated
according to season as i t was n o t fe a s ib le t o keep an a cc u ra te monthly
check on th e d ates o f dropping.
THE FAUNA
The follow ing ta b le (Table I ) shows th e number of s ig if ic a n t
p red a to r and prey species observed on th e se c tio n a t th e end o f each
season as in d icated *
(The seasons a re th re e month p erio d s—December,
January and February being w in te r, etc* )
For convenience in study the
anim als have been placed in to more o r le s s n a tu ra l group s—ra p t o re s,
.
c a rn iv o re s, o th e r b i r d s , and other mammals. Arabic numerals in d ic a te
the number o f in d iv id u als observed on th e a re a in t h a t season; Roman
numerals in d ic a te th e month of t h a t p a r tic u la r season in which t b m igrant
o r h ib ern a tin g anim als were f i r s t o r l a s t seen according to th e time of
y e a r.
An a ccu rate count was obtained o f a l l th e p red a to rs except w easels.
A c a re fu l e s t im t e a f t e r checking tra c k s and sig n would place th e a c tu a l
number seen a t about h a lf th e number p re s e n t.
A s a tis f a c to r y check was made on th e number o f b ird s p re se n t except
during th e sp rin g when i t i s estim ated th a t only th re e -fo u rth s of the
p a rtrid g e s were flu sh e d .
This number is based on th e number o f p a rtrid g e s
seen during th e previous month and th e number o f a d u lt b ird s flu sh e d in
the f a l l .
I t was extrem ely d i f f i c u l t to g e t population numbers of th e sm all
mananals so index fig u re s a re used t o show t h e i r abundance.
These in d ic es
a re used to show th e flu c tu a tio n w ith in a sp ecies o n ly , and n o t the
r e la tiv e e lse o f populations o f d if f e r e n t species on th e a re a (although
t h i s i s in d ic ate d in a s lig h t d e g re e ).
In th e f a l l of 1939 the Mlorotus
population had reached th e upper l im i t o f i t s cycle and during th e sp rin g
o f 19^0 had been reduced to a f r a c tio n of i t s former s i z e .
E stim ates of
numbers of a c tiv e runways and numbers seen in a given len g th of time
suggest t h a t the number had dropped to le s s th an a te n th of th e previous
Table I .
Numbere o f p rin c ip a l speoiee observed on th e area by season.
*
RAFTORES
C ircus hudsonius . . . . .
Buteo b o re a lis calu ru s • . . .
Buteo lagopus s . johannis . . .
Bubo v irg in ian u s o c c id e n ta lis
Asio w ilsonianus ................. . .
I
s-4 OX
<8 KX
(=4 *■
yd O
Kx
S= -
M-
4 -iii
2- i i i
I
2
1- i
we.
I
I
2- i i
3- i i i
1- i i i
1- i
I
I
I
CARNIVORES
Canis la tr a n s . . . . . . . . I
M ephitis hudsonica . . . .
Mustela longicauda . . . . . . .5
F e lls domesticus ................. . . 6
I sto
I
3
I
I
If
SS
rH
5 S
-
I
to we.
3 -iii
2- i i i
1- i i i
I
1- i i
I
I
I
3
k
2
I
6
5
2
OTHER BIRDS
Perdix p , p erd ix . . . . . . . 22
10
2
12
36
9
25
1
Phasianus colchleus torquatus;
5
h
3
lo o t
lo o t
lo o t
lo o t
lo o t
lo o t
Pica p ica hudsonia . . . . . .lo o t
P asser dom esticus . . . . . .
(la rg e numbers around a l l b u ild in g s and brush)
2-1
Faloo sp arv ariu s . . . . .
2
CU
#
*
OTHER MAMMALS
M icrotus pennsylvanicus modestusl „
M icrotus nanus
‘
J 10
Lepus townsend! . . . . . . . . h
C ite llu s ric h a rd so n ii . . • •
Ondatra s ib e th ic a . . . .
:
10
7
I
5
:
2
% -ii
I
I.
I
xI
I
2
X-I
I
2
h
3
I
x -i
I
♦Summer fig u re s in a c c u ra te , d ata c o lle c te d by inexperienced f i e l d man
—16“
p o p u latio n .
The reason f o r t h i s sudden decrease i s unknown.
Numbers of
jack r a b b its on th e se c tio n were obtained q u ite a c c u ra te ly a f t e r th e f i r s t
snow fall.
The number o f ground s q u ir r e ls was n o t obtained b u t a seemingly
c o n sta n t, moderate population remained on th e a re a , in cre asin g in th e spring
and d ecreasing slow&y in th e summer and f a l l to a number about co n stan t
fo r any sp rin g census.
This tendency o f populations to remain near th e
maximum carry in g c ap acity of th e range has been noted by many.
King i s
quoted by E rrin g to n (1938) as observing an increased v u ln e r a b ility o f a
top-heavy ru ffe d grouse population in Minnesota during th e w in te r.
By
sp rin g th e u nusually la rg e number of grouse s ta r tin g was reduced to a
number about average f o r th e two previous sp rin g s.
THE BIOLOGICAL COMPLEX
Weather and Animal Movements
Predator and prey populations changed considerably during the time o f
the study.
This i s only natural because any small change in environment
may i t s e l f change a pattern or may se t o ff a se r ie s o f subsequent changes
which w ill have a much greater e ffe c t on the population.
recognized the dynamic quality o f ecological processes.
Adams (1925)
"There i s no fixed
r e la tiv e balance o f nature, i t i s always undergoing change* the major r e la ­
t iv e balance was changed by the Indians, and much more by the European. • •
These changes impose new r e la tiv e balances upon a l l w ild lif e , including
predators, and thus th is unending process o f adjustment to change
continues."
Most o f th e changes on th e study a re a can be tra c e d d ir e c tly to
w eather co n d itio n s and population
s h i f t s (P la te I I ) •
-1 7 Two American rough-legged hawks a rriv e d on th e a re a Kbvember 2 2 , 1939»
apfl re m in e d th e re throughout the w inter*
The r e d - t a i l e l e f t th e f i r s t of
Deoenflber and th e l a s t marsh hawk was seen the middle of th e same month.
Tto prey anim als remained in good con d itio n during th e f a l l , which was a
time o f overlapping periods of s ta y of th e m igrant r a p to re s , so th a t th e
prey sp ecies went in to th e w in ter in unusually good c o n d itio n .
The w in te r re s id e n ts of th e s e c tio n included two ro u g h -leg s, one
g re a t hom ed ow l, two long eared ow ls, a coyote, a t l e a s t one skunk, and
about twelve w easels* 25 European p a rtr id g e s , 7 jack r a b b i t s , and a la rg e
pop u latio n o f meadow m ice.
Heavy, deep snow in th e f i r s t th re e months o f 1940 worked a hardship
on most o f th e p red a to r and prey anim als, but ra p to re s , and mice which liv e d
under th e snow alm ost e n tir e ly , were n o t e ffe c te d a s g re a tly a s th e o th e rs .
Coyotes c o n tin u a lly blundered in th e deep snow and had d i f f i c u l t y g e ttin g
fo o tin g f o r a sudden sp rin g .
Babbits fa re d l i t t l e b e tte r* t r u e , th ey
stayed on to p o f th e l ig h t c ru s t most o f the tim e , b u t when s t a r t l e d th ey
would k ick through th e c ru s t and be hard put to re g a in t h e i r fo o tin g so
th ey could escape.
The p a rtrid g e s got along m oderately w e ll b u t were
v u ln erab le t o a tta c k when they were down in th e snow o r away from th e
b ru sh .
T heir i n i t i a l spring in the a i r was considerably hampered b y th e
depth of th e snow and th e f i r s t few wing b e a ts l o s t impetus by s tr ik in g
th e snow.
A ll th e snow had m elted by th e l a s t of March end about th a t tim e th e
f i r s t marsh hawk retu rn e d f o r th e summer. N early two weeks l a t e r th e
r e d - t a il s a rriv e d .
During th a t time th e rough-legs were retu rn in g to
18*
—
t h e i r summer haunts in th e n o rth .
In th e sp rin g and e a rly summer th e re
was a sudden and ra d ic a l decrease In th e mouse population so t h a t i t
became only a f r a c tio n o f th a t of th e previous summer.
The summer was
average f o r th e v a lle y .
A summer census showed p re se n t on th e a re a th r e e r e d - t a i l s , fo u r
marsh hawks, one g re a t horned <wl, one coyote, a skunk, and 12 w easels;
35 European p a rtr id g e s , fo u r jack r a b b i t s , a sm all popu latio n o f m ice,
and a moderate population of ground s q u irre ls •
The a r r i v a l o f grasshoppers and o th e r in s e c ts in th e spring took a
co n sid erab le load from the v e rte b ra te prey f o r n e a rly a l l of th e p redators
on th e a re a a te considerable qi a n ti t i e s of in s e c ts during th e summer a s
s c a t and p e l l e t analyses showed.
In the e a rly f a l l se v era l ring-necked
pheasants (Fhaslanus oolchifots to ro u a tu s) m igrated t o th e area thus
in tro d u cin g a new element in to th e pop u latio n c o n fig u ra tio n .
The disappearance of in s e c ts w ith the advent o f cold w eather s h ifte d
th e d ie t o f th e s e p red ato rs alm ost com pletely to mice a g a in .
The food
and cover p la n ts on th e a re a were fro zen in m id -fa ll and th e prey sp ecies
were more exposed and in poorer co n d itio n f o r w in te r weather which s e t in
th e l a t t e r p a r t of October.
The w in ter o f I 9I4.O-J4I was somewhat co ld er and more extended th an
th e previous w in te r.
This w in te r popu lation was composed of one g re a t
horned ow l, one coyote, a t l e a s t one skunk, a dozen w easels; 20 p a rtrid g e s
th re e rin g -Aacked p h easan ts, f iv e jack r a b b its and a moderate population
o f m ice.
No o th e r ra p to rs w in tered on th e a re a and th e owl t h a t had been
re s id e n t th e re fo r some tim e s h ifte d h ie hunting to more fav o rab le p a rts
-1 9 -
about the f i r s t o f Fehruary.
Oa term in atio n o f th e study March 31, 1941, •
no hawks had retu rn e d from the south and the p a rtrid g e p o pulation was
reduced to about 18—20, otherw ise no popu latio n changes were evident f o r
-
the sp rin g of 1941.
During th e w inter th e apparently le s s a v a ila b le food and the
decrease in the amount of s a tis fa c to ry cover tended to keep the p red a to rs
more widely d is trib u te d than in the summer.
I t was found th a t the anim als
d a ily hunted almost a l l o f the a re a w ithin t h e i r normal d a ily c ru isin g
ra d iu s.
There seemed to be le s s overlapping o f hunting t e r r i t o r y among
sim ila r p re d a to rs than i n th e summer.
I t was.found th a t scavenging was
more p rev a len t i n th e w in ter months, presumably because o f la c k of s u ffic ie n t
amounts o f o th e r foods.
D e fin ite evidence o f both carnivore and ra p to re
scavenging was found in th e snow in th e remains o f chickens, magpies and
a newborn c a l f picked clean.
Increased p re d a to r p re s su re , caused i n p a rt by th e in flu x of
m igratory sp ecies, somewhat decreased th e r e la tiv e a v a i la b i li t y o f the prey
sp ecies (asid e from th e super-abundant mice in 1939-bo) fo r a short time
in the f a l l and fo r a s lig h tly longer time in th e spring (see p la te I I ) .
There was very l i t t l e d ire c t antagonism between owls and hawks
but th e re was a g re a t deal o f d ir e c t com petition in th e way o f p ressu re on
the same prey sp ecies, th e hawks e x e rtin g p re ssu re in th e daytime and the
owls a t n ig h t.
In th e e a rly morning and l a t e evening hawks and owls were
seen hunting over th e same a re a sim ultaneously, but th is was not commoh.
These two raptoras e ffe c te d a never-ending p ressu re on rodent populations
and the th r e a t o f a cc id e n ta l p re d a tio n on game species was always p re se n t.
—20—
day and night.
A coyote, two skunks and about 12 weasels roamed the area
constantly, the w easels; seldom covering an area more than a hundred yards
in radius during one day.
Except a few hours at noon these mammals hunted
the area almost unceasingly, some o f them hunting throughout the n ig h t.
Kearly the en tire section was system atically hunted the year round by at
le a s t s ix house c a ts.
Thus another factor was added to the already complex
"balance" e x istin g on the section .
Flora-fauna Relationships
There are certain ecolo g ica l a ssociation s which generally need
no explanation, but when interp retin g predator-prey phenomena i t i s w ell
to have the d e ta ils o f the situ a tio n w ell in mind.
Wild populations tend to e x is t in proportion to the amount o f
ed g e-effect.
I t i s expected that animals w ill be found most frequently
next to those edges; the data gathered on th is study are in no way
contradictory.
Along sloughs and ditches in pastures there was a rather constant
population o f meadow mice.
Here they were in th eir preferred habitat—wet
ground with a heavy overgrowth o f grass which perm itted them to build
th eir tunnels on top o f the s o il y et remain hidden.
Hummocks o f ground
on which willows stood in the sloughs gave the mice a good place in which
to b u ild th e ir n ests and push th eir tunnels.
The rank, green vegetation
which grows in the sloughs afforded the mice a never ending supply of
green food m aterial, even in winter.
The marsh hawk, which shows a
-2 1 -
p red ilectio n fo r meadow mice, was seen coursing over the sloughs and wet
pasture lands.
B ed-tailed hawks and occasion ally rough-legs were seen
quartering the sloughs In search o f prey.
same area.
In the evening owls hunted the
The crepuscular coyote hunted the sloughs taking heavy t o l l o f
the mice i t found there.
Although weasels and skunks were le s s sp e c ific
in the choice o f land which they hunted, they were often seen snooping here
and there up and down the sloughs in search of prey.
Wet d itch es, and the wet ground near them, present a d ifferen t
type o f flo ra —one tra n sitio n a l "between hydrophytic and mesophytic,
The
grass found there was s t i l l mainly "blue grass with a heavier mixture o f the
more wiry Cexex and Elymus.
There were numerous forhs along the ditches
and a rather dense stand of rose "bush, snowherry, willow s, and alders
alternated with stretches on which the only cover was t a l l grass ( Elymus
and Bromus) and various forhs.
There were some mice here hut considerably
fewer than along the sloughs.
The t a l l grass and brush afforded excellen t
cover fo r rabbits and partridges the year round.
Invading the ditches and small
streams in the more open areas were a few muskrats which e a s ily f e l l prey
to the larger predators because o f lack of cover.
B ed-tailed and American
rough-legged hawks end a great horned owl hunted along these ditches and
moist areas.
Coyotes, skunks, and house cats found ample stalk in g cover.
Dnring the day hawks were seen lo a fin g and owls sleeping in the willow s,
a ld ers, and occasional t a l l cottonwoods along the d itch es.
The hawks and
magpies used the brush as restin g cover at night as did the owls, skunks,
and coyote in the daytime.
hind proved th is p oin t.
Animals flushed from cover and signs l e f t be­
Numerous small birds, including a large number of
-2 2 -
Engliah sparrows, in h a b ite d t h i s "brushy are a 631 year and domestic chickens
freq u e n tly hunted along i t .
There were th re e farms on th e a re a and seven ad jo in in g i t ; a l l
o f th ese u n its had some chickens which, p a r tic u la r ly in summer, foraged
as f a r as h a lf a m ile from the "buildings.
These chickens fed along fences
and brush where the h&wks, owl, and coyote were to be found hunting or
r e s tin g , y e t the only p re d a to r a c tio n a g ain st them (as f a r as could be
ascertain ed ) was scavenging on dead chickens
dumped out by th e farm ers.
The p a stu re a re as on th e se ctio n were e ith e r dry o r had sub­
i r r ig a te d borders along d itc h es and sloughs.
The dominant cover i n the
p a stu re s was b lu e g rass w ith s c a tte r in g brome and tim othy in p a r t s .
Along
th e fence rows th e re was some rose brush and e ld e r as w ell a s a few lone
cottonwoods.
The more damp p a r ts o f th e p a stu re s were w ell populated by
meadow mice and were f r e e ly run over by jac k ra b b its .
In th e sp rin g , summer
and f a l l numerous ground s q u ir r e ls ( C lte llu s rlc h a rd so n il) were found i n the
p a s tu re s , p a r tic u la r ly along fences and high d itc h banks.
The p a stu re s
were hunted by a l l the ra p to re s on th e a re a , and th e ir borders were
thoroughly p a tr o lle d by coyotes, skunks, and w easels.
The damp p a stu re
land seemed to be the hunting ground most in common to th e p re d a to rs o f
th i s are a.
The f ie ld s on th e se c tio n were of th ree types during th e w inter;
f a l l plowing, a l f a l f a , o r wheat stu b b le.
The plowing supported p r a c tic a lly
no game o r b u ffe r p opulations except fo r the few in d iv id u a ls along the
borders o f the f i e l d s where they ap p aren tly had m igrated from the populous
neighboring a re a s.
-2 3 -
The a l f a l f a supported heavy populations of meadow mice and along
the edges fu rn ished food fo r th e ra b b its and p a rtrid g e s in th e summer.
E arly in the w inter the wheat stu b b le o ffe re d cover and food to a la rg e
p o p u latio n of meadow mice end numerous p a rtrid g e s .
Many coyote sc a ts and
skunk sign were seen along th e edges of the stubble f i e l d s .
The p a rtrid g e s
spent a la rg e p a rt of t h e i r time in th e edge of th e stu b b le, around straw
p i le s and along brushy fence rows during th e e n tir e time o f study.
In th e
summer when growing crops were found on most o f th e f i e l d a re a s, th e rodent
and game p o p u latio n s moved In q u ite ra p id ly to take advantage o f th e abundant
food and cover which crop land o f f e r s .
The change o f cropping p ra c tic e s and consequent s h i f t o f plowed
a reas on the se c tio n during th e summer and f a l l o f 19*10 had a very marked
e ff e c t on th e p o s itio n and movement o f animal p o p u latio n s.
With th e l a t e
summer plowing of la rg e p o rtio n s on the e a st sid e o f th e se c tio n a l l
p o p ulations s h ifte d west to p a stu re s and unplowed crop lan d s.
By n o tin g
the types o f farming p ra c tic e s on th e v ario u s p a r ts o f th e sectio n (see
p la te I) i t i s p o ss ib le to p lac e approxim ately the p o s itio n s o f co n centrations
o f sm aller prey and hence a lso the a re as where one would fin d the p re d a to rs.
p red a tio n P a tte rn s
Mice;
In w inter the meadow, mice on th e a re a were found to b u ild n e sts
anove th e ground and under the snow.
A l i t t l e dome ic e d over by the h eat
o f th e i r bodies re s u lte d and alm ost in v a ria b ly a sma l l vent was formed
d ir e c tly above the n e s t.
of G lacier Park.
B ailey (1915) no tes t h i s behavior i n th e M icrotus
"TRhen th e f i r s t snow f a l l s they (M lcrotus) plow l i t t l e
tunnels over the surface o f the ground, and these "become hardened and
throughout the winter are avenues o f tra v el, . . Many winter n ests are
"built on the surface o f the ground and occupied u n til the snow disappears."
From these n ests on top o f the ground tunnels ramified through the snow,
as extensive in a horizontal plane as are th e ir subterranean tunnels in
summer.
Weasels and skunks made a habit o f v is it in g these n ests which
they located by the small vent. Weasels frequently explored the Inside
/
■
of the l i t t l e iced domes, sometimes even working out in to the tunnels, only
to come back out through the place they entered and go on to another n est.
Skunks hunted about these "houses" in a manner sim ilar to the weasels but
le s s frequently actu ally entered the n est.
Piper ( 1909) says, "They (skunks
and weasels) are most p ersisten t enemies o f mice."
Magpies opened the
mouse n ests as soon as they could reach them through the opening in the
snow.
The deep snow and the fr o s t free ground were a boon to the mice.
They b u ilt th eir homes and tunnels securely under a foot or more o f snow,
gathered green food a l l winter long and liv e d comparatively free from attack.
Hawks and owls were seen to dive in to the snow a fter mice, frequently
completely burying themselves and emerging now and then with a mouse, but
more often without i t .
The predatory mammals liv e d l i t t l e b e tter , usu ally
returning from a plunge in to the snow with empty claws.
In sp ite of these
depredations the mice liv e d comparatively free from disturbance while the
snow was deep on the ground.
And in sp ite o f th e ir r e la tiv e security they
furnished the stap le winter food o f a l l the predators on the area as can be
-2 5 -
seen in tab les I I , I I I , and IV.
ground sq uirrels:
ground sq u irrels, rhlch are preyed upon considerably
by the larger raptores and predatory mammals, ceased th e ir a c tiv ity for the
most part by the la s t week in September and hence th e ir buffer action disap­
peared.
Ko October p e lle t s or sca ts contained ground squirrel remains.
Their hibernation occurred at a time when predator pressure was increased
by the in flu x of migratory raptores.
By the middle o f March the ground
sq u irrels came out o f hibernation, ju st a fte r the winter resident raptores
had gone north:
Their appearance from hibernation at th is time reliev ed
some o f the str e ss on other populations at a time when breeding, choice o f
nesting s i t e s , etc.,'m ade the la t t e r intolerant o f th e ir winter concen­
tra tio n s and le s s cautious in th eir hab its.
Several early April scats and p e lle t s showed predation had already
begun on the ground sq u irrels.
Fur and bone fragments in scats and p e lle t s ,
and sk u lls ly in g in the f i e l d showed that ground sq u irrels were preyed on
quite c o n sisten tly as long as they were a v a ila b le.
The la s t three o f
Leopold's fiv e deleteriou s e ffe c ts o f buffers (p .9) applied aptly to the
ground sq u irrels.
At the same time they were of great value in reducing
pressure on other sp ecies throughout the summer.
Coyote:
*
The coyote, a n ative of the p lain s country, has stayed there while
the farmers have moved in around i t .
By changing i t s ways so as to liv e
with the farmer i t has been able to stay in i t s old ter rito r y in sp ite o f
e ffo r ts to exterminate i t .
At times i t hunted p r a c tic a lly in the farm yards as tracks proved.
.Frequently during the winter coyote tracks were followed along the willow
- 26-
p atch es, "brushy fence rows, and out across open f i e l d s .
The tra c k s showed
th a t the coyote had "been hunting th ese areas q u ite c a re fu lly , not over­
looking any p o s s i b i l i t i e s —mice, ra b b its , p a rtrid g e s , o r whatever e ls e
n ig h t occur in i t s p a th .
In l a t e November, 1939, th e remains o f a la rg e
muskrat k i ll e d and eaten by a coyote were found under a willow about f i f t y
yards from a sm all stream .
p re d a tio n .
This was w ithout doubt a case of a cc id e n ta l
The p la c e where the muskrat was caught was c lo se to a fence
and dry d itc h which th e coyote h a b itu a lly used w hile hunting th a t side o f
the p a s tu re .
coyote.
In another p a rt of th e se c tio n a marsh hawk was k i ll e d by a
Fresh tra c k s and a newly dropped sc at were found a sh o rt d istan c e
from the k i l l .
A pparently th e coyote had discovered the hawk e a rly in th e
morning as i t was sle ep in g on th e ground near some scrub willows in a
slough and had k i l l e d i t .
Table I I summarizes th e food h a b its of the coyote a s determined
by sc a t a n a ly sis only.
Other sign found in the f i e l d show th a t th e coyote
had a lso eaten a m uskrat, c a rrio n chicken, a magpie, a marsh hawk, a Jackra b b it, and a ground s q u ir r e l.
The b ird s were taken i n th e w in ter, the
mammals in the sp rin g and f a l l .
Mice formed th e main food o f the coyote throu^iout th e y e a r but
o th er mammals a lso were taken during the summer; th e la r g e r s iz e o f th e
l a t t e r prey would make them an im portant fa c to r i n th e coyote’ s d ie t.
In se c ts were taken in la rg e enough numbers to make them im portant during
the warmer months.
Column B shows th a t they were found in q u ite la rg e
numbers in 1/6 to I / 3 o f the summer s c a ts .
B irds were preyed on only
during the w in ter and then were an in freq u e n t item .
The sparrow -size
T able I I . S ea so n a l summary o f c o y o te s c a t a n a l y s i s . Column "A"— a v era g e number o f fo o d Item s
p er s c a t , colum n "B"—number o f s c a t s In w h ich t h a t fo o d ite m a p p ea red . (S e e p l a t e I I I . )
1939
F a ll
W inter
T otal number o f s c a ts
29
A
B
24
A
1940
Summer
Spring
12
B
A
F a ll
6
B
A
B
MAMMALS
M icrotus
C ite llu e
O thers
I*. 23 29 3.75 24 4.83 12
4.21 29 3.75 24 4.67 12
•03 I
.04 I
.16 2
INSECTS
A crididae
C oleoptera
Noctuidae la rv a e
Others
.•52
.17
.17
5
3
2
.83
.33
4
3
.50
.33
I
I
S•
?
.50
I
.17
I
•25
.25
BINDS
Sparrows (?)
P a rtrid g e s
Others
.13
.09
3
2
•°4
I
3.67
3.67
A
23
12
B
4.65
.17
3.00
1.43
.05
6
3
3
2
I
3
3
.09
.09
2
2
.21 4
.17 .4
.04 I
.09
.05
.04
2
I
I
.25
.25
2
2
•13
•13
2
2
MISCELLANEOUS
.07
.13
3
.08
I
.17
3
See appendix, ta b le V II, f o r in d iv id u a l s c a t a n a ly s is .
A
6
B
A
6 4.17 23 4.33 12 1.83
6 4.17 23 4.33 12 I .83
PLANTS
G rass, straw
Others
2
1941
Spring
W inter
.08
I
.08
I
.08
.08
I
I
B
6
6
-2 8 -
M rds u su a lly taken could "be h a rd ly more In d ic a tiv e o f food h a h lts than
a sin g le mouse.
I t I s q u ite p o ss ib le th a t many o f th ese avian prey were
taken "by sa n ita ry p re d a tio n .
Some extraneous p la n t m a te ria l was found In
n e arly every sc at analyzed, only exceptional Item s o r amounts were noted In
the ta b le .
M iscellaneous Item s Included a considerable amount o f sand
( g r i t from the g izz ard o f a p a rtr id g e ) , 4 Nematode p a r a s ite s , p ro g lo ttid s
from a Cestode, one small Gastropod, and some wood, stones and d i r t .
Skunk;
From the few skunk sca ts availab le (see table
;x)
i t appears that
skunks fed almost e n tire ly on mice in the winter and on in se c ts and mice
in the summer.
A summer scat (not included in the table) found at the
beginning o f the study consisted e n tire ly of grasshopper remains.
Those
taken during the study u su ally had at le a s t one mouse represented.
European p a rtr id g e ;
During th e w inter months the p a rtrid g e s became
extremely wary and i t was d i f f i c u l t to approach w ith in 50 yards before
they flushed.
In w inter the p a rtrid g e s could be seen along th e d itc h
banks where th ere was l i t t l e snow p ick in g up seeds, green g ra ss, and
g ra v e l, and taking dust b a th s.
At o th er tim es they frequented straw p i le s
and the stubble next to brush rows.
They would sc ra tc h through 6-8 inches
o f snow to get food and g r i t underneath.
By mid-March th e p a rtrid g e s
were alread y p a ire d end claim ing n e stin g grounds.
In sp rin g , summer and f a l l they were more s e c re tiv e in t h e i r
h a b its and la y w e ll, flu sh in g suddenly a t sh o rt d ista n c e s .
Throughout th e
summer they spent most o f the time out in the f ie ld s and in p a stu re s w ithin
a hundred yards of cover.
6-20 members.
In the f a l l they congregated in coveys of from
Shortly a f t e r heavy w inter s e t in the coveys broke in to
sm aller groups and sev eral l e f t th e a re a , so th a t by sp rin g th e re were
-2 9 -
from 8-10 p a ir s l e f t on the s e c tio n .
Apparently 9-10 p a ir s i s th e
approximate c arry in g cap acity o f t h is se ctio n f o r n e s tin g p a rtrid g e s .
In t h i s region th e p a rtrid g e popu latio n i s lim ite d mainly hy th e amount
o f a v a ila b le food in w inter, and secondarily in most in sta n c e s hy the
amount o f cover.
Eawkst
A ll o bservations on hawks were made according to species but i t
was not fe a s ib le to sep arate p e l l e t s , so p e l l e t analyses were grouped as
food h a b its o f “hawks on the area*.
Marsh hawks may be seen any time in the d ay lig h t hours coursing
back and f o r th a cro ss sloughs o r f i e l d s hunting mice.
They f l y t i r e l e s s l y
only 4-6 f e e t above the ground, making sudden plunges earthw ard as they
see some quarry.
O ccasionally they r e s t a few m inutes s i t t i n g on th e
ground, o r idien w orried by a group o f magpies they may take s h e lte r in
some brush fo r a sh o rt tim e.
On no occasion were these hawks seen to eat
anything but mice, although i t i s q u ite probable th a t they hunt small
ground s q u ir r e ls in the summer.
The marsh hawk e a ts many in s e c ts during
the warmer months.
The r e d - t a i l s a re th e hawks one commonly sees c ir c lin g high in
the a i r .
When hunting they may q u a rte r th e f ie ld s end p a stu re s lik e the
marsh hawk o r spend much time s i t t i n g on a p o st o r in a tr e e watching fo r
some la rg e r prey.
During the summer the r e d - t a i l s apparently prey to a
considerable ex ten t on ground s q u ir r e ls , b u t i n th e sp rin g and f a l l they
have to re ly alm ost e n tir e ly on mice f o r sustenance.
The American rough-legs come down from t h e i r f a r n o rth n e stin g
region to w in ter in th e northern s t a te s .
From t h e i r a r r iv a l in November
-3 0 -
1t i l l th e ir depairture in Pehniary o r March t h e i r s ta p le food i s mice.
At tim es they may chance on a p a rtrid g e , ja c k ra h h lt, or in h ard weather
may even "stoop" to e a tin g c a rrio n , as do most o th er p re d a to rs In th e
w in ter.
The rough-legs were watched c a re fu lly and were observed to p rey
only on mice during t h e i r stay here in th e w in ter.
A summary o f hawk p e l l e t analyses i s given in ta b le I I I .
No
p e l l e t s were found in th e w in ter and spring o f I 9UI because th e summer
hawks had a l l m igrated south before w in ter s e t in , no n o rth ern hawks
w intered h e re , and th e summer re s id e n ts had not retu rn e d when the study
was term in ated .
Though th e re were fewer hawks in th e e n tir e v a lle y in the w inter
o f I 9U0-U1 the absence of hawks from t h is p a r t i c u l a r se c tio n may have
been c lo s e ly a sso c ia te d w ith the lo c a l s c a rc ity o f mice.
Itymond (1939)
b e lie v e s " I t i s the prey which determ ine th e number o f t h e i r p re d a to rs.
P red ato rs do e ffe c t to some ex te n t th e numbers o f th e i r prey but th e
i n i t i a t i v e l i e s w ith th e p rey ."
The sta p le food o f hawks on th e se c tio n a t any time was mice.
Ground s q u irre ls were preyed upon in th e warmer months.
A ra b b it, a
pocket gopher ( Thomomys talp o ld ea) and an u n id e n tifie d small carnivore
were a lso taken in the summer.
The pocket gopher must have been picked
up in th e f o o th ills 5-6 m iles away a s none have been found in th e i n te r ­
vening a re a.
These mammals formed a m a te ria l p o rtio n o f th e d ie t o f the
hawks re s id e n t on th e a re a i n th e summer.
TShen a v a ila b le , in s e c ts were
taken in q u a n titie s s u ffic ie n t to make them a r a th e r im portant source o f
food.
Some b ird s were taken but they probably played an in s ig n ific a n t
TABLE I I I .
S ea so n a l summary o f hawk p e l l e t a n a l y s i s . Column "A"— a v era g e number o f fo o d ite m s
p er p e l l e t , colunfb "B"— number o f p e l l e t s i n w hich th a t fo o d ite m appeared.
(S e e p l a t e IV.)
1939
Winter
F a ll
T otal number of
p e ll e t s
MAMMALS
M icrotus
C ite llu s
Others
I1ISSCTS
A crididae
C oleoptera
C oleoptera larvae
Koctuidae la rv a e
Others
50
23
B
1940
Summer
Spring
3]
A
B
A
1.96
1.94
50
50
2.28 28
2.28 28
.02
I
.02
I
.34
.20
.OS
.02
9
7
1
1
.35
.03
.10
7
I
3
.16
.06
I
2
.04
A
B
2 .4 l 31
2.39 31
A
63
B
F a ll
A
54
B
1.75 63 1.70 54
1.70 63 1.68 54
.02 I
.03 2
.02 I
.68 20
.29 11
.36 9
.03 2
-52 19
.23 10
.21 8
.04 2
.02 2
.02 I
BIRDS
Sparrows (?)
.02
.02
1
1
.05 I
.05 I
.03
.03
I
I
BLASTS
Grass, straw
Borbs
Grain
.OS
.02
.02
.04
2
I
I
2
.04 I
.04 I
.13
.10
3
1
#
.03
1
.04
.02
,06
2
MISCILLAKZOUS
Winter
.03
.03
2
2
.06
.06
3
3
.06
3
2
I
1941
Spring
0
A
0
B
B
A
,
'
ro le In the food h ab its o f these hawks.
Owl;
The great homed owl hunts nocturoally, picking up whatever prey
i t s powerful talons can grasp.
Table IV shows the food habits of the
great homed owl as learned from p e lle t a n a ly sis.
: The owl l e f t the area early in February, igU l, so few p e lle t s
were found in the winter and none in the spring.
The p rin cip al food o f th is raptors was mice.
Ground sq uirrels
played a small part in the food o f the owl because they are s t r ic t ly
diurnal and the owl i s crepuscular and nocturnal.
In se cts, mainly the
larger b e e tle s and grasshoppers, were taken quite often .
Birds are a
sig n ific a n t, though hardly important, item in the ow l's d ie t.
They were
taken, perhaps, mainly through accidental predation.
Magpies:
Magpies were sometimes seen worrying marsh hawks or r e d -ta ils
a fter they had caught a mouse or some other b it o f prey.
The magpies
even trie d to rob the b ig rough-legs that wintered on the area.
They
are a most omnivorous bird—robbing granaries, k illin g mice, stealin g
from other birds o f prey, hunting out carrion and otherwise eatin g almost
anything they can find.
Frequent evidence of predation on mice was seen
throughout the winter, sweeping t a i l marks, a b it o f v iscera and fur in
the enow t e s t if ie d to th is habit o f magpies.
Almost Invariably one or two
magpies were frightened from any carrion that happened to be ly in g exposed.
General;
Despite some radical changes in the predator and prey
populations during the time o f study the predation pattern remained
e sse n tia lly unchanged throughout that time.
The follow ing p la te and
tab les c le a rly in d ica te the nature o f predation that occurred on the area
IABLE 1 7 . S ea so n a l summary o f owl p e l l e t a n a l y s i s . Column "A"— a v era g e number o f fo o d ite m s
p er p e l l e t , column "B"—number o f p e l l e t s i n w hich t h a t fo o d ite m a p p ea red . (S ee p l a t e I V .)
1939
F a ll
W inter
t a l number o f
p e lle ts
?1
A
MAMMALS
M iorotus
C ite llu s
Others
20
B
A
2.19 31
2.19 31
191+0
Summer
Spring
A
B
28
B
1.1+5 20 2.93 28
1.1+5 20 2.89 28
A
10
F a ll
B
A
111
W inter
BIRDS
Sparrows (?)
P a rtrid g e s •
.09
.09
3
3
•05
•05
I
I
PLANTS
G rass, straw
Grain
Others
.16
.06
.05
.07
5
2
I
2
.10
.10
2
2
MISCELLANEOUS
.05
I
7
1+
5
I
8•
.97
•U3
.1+8
.06
2
.11
I
.11
I
A
B
1.50 10 1.93 11+ I .85 12
1.20 10 1.86 H+ 1.85 12
.10 I
.07 I
.10
.10
.07 2
•03 I
.01+ I
.07
0
12
B
.01+ I
INSECTS
A crididae
Coleoptera
Noctuidae la rv a e
Others
2
See appendix. Table IX, f o r in d iv id u a l p e l l e t a n a ly s is .
I
I
1941
Spring
.07
.07
I
I
.07
.07
I
I
A
B
-3 4 -
under c o n sid era tio n .
As one may in f e r from p la te I I , th e g re a te s t p re ssu re on the
p rey occurs in the f a l l during the m igration o f ra p to rs and perhaps more
severely in th e sp rin g when th e prey p opulations a re moving about a f t e r
rig o ro u s weather, have a lowered re s is ta n c e to adverse environment, and
a re in the process o f fin d in g mates fo r the ensuing season.
During the
sp rin g , a p e rio d o f u n sta b le populatio n s in an u n sta b le p h y sio lo g ic al and
psychological s ta te , a r e la tiv e ly h igh p ro p o rtio n o f th e prey species i s
su sc e p tib le to a tta c k by hungry p re d a to rs.
A ll the im portant p re d a to rs obtained some of t h e i r food through
a c c id e n ta l o r sa n ita ry p re d a tio n .
Such p red a tio n probably included the
p a rtrid g e s , ground s q u ir r e ls , and muskrat k i ll e d .
This i s not an unde­
s ira b le th in g fo r, as Cottaa and Kelson (1933) say, "predation w ith in
reasonable lim its e x e rts a wholesome e ff e c t by curbing reproduction of
the le s s f i t in d iv id u a ls and th e re fo re m aintaining q u a lity and prev en tin g
spread o f d ise a se ".
In c id e n ta l p red a tio n ra re ly assumes p ro p o rtio n s
d e trim en tal to the maintenance o f s a tis fa c to ry p o p u latio n s.
B ating c a rrio n was common to a l l th e p re d a to rs .
Many o f these
cases were a c tu a lly observed and o fte n sign found around c arca sses showed
p la in ly th a t i t was an a c t o f scavenging and not a fre s h k i l l .
Dead
anim als and chickens were seen in th e f i e l d and l a t e r evidences o f
scavenging on th ese c arcasses were to be seen p la in ly .
Unless th e re i s
f i e l d observation to a id in in te r p r e ta tio n i t i s o ften im possible to t e l l
from a fe a th e r in a sc a t whether i t was prim ary o r secondary p red atio n
or scavenging.
-35
Observed cases of ir r e g u la r p red atio n a re noted below:
Table 7 .—Ir r e g u la r food h a b its o f p red a to rs stu d ie d '
A c c id e n ta l
Great hom ed owl
Hawks
sparrows
sparrows
Coyote
muskrat
Skunk
Magpies
marsh hawk
—
sparrow
S a n lta r y ( T )
S cavenged
p a rtrid g e
ground
s q u irre l
p a rtrid g e
— —
mice (?)
chicken
magpie, chicken
p a rtrid g e , magpie
chicken
dead c a l f
dead c a l f
b lac k b ird , chicken
a l l dead anim als
Numbers of mice eaten by p re d a to rs were determined fo r th e most
p a r t by counting th e number o f in c is o rs found in th e sc a t o r p e l l e t .
O ccasionally long le g bones were used when no o th e r determ inative
c h a ra c te r was p re s e n t.
A mass o f fu r without bones was counted as one
mouse even though i t obviously rep resen ted more than one.
A ll numbers
were taken from th e g re a te s t number o f determ inative bones p re s e n t.
The
mice were a l l id e n tif ie d as M lcrotus pennsylvanicus modestus and M. nanus
by examination o f specimens caught in tra p s .
Only M icrotus were trapped
but Peromyscus a rte m isia e ( T ) was determined to be on th e a re a by
id e n tif ic a tio n o f a p a ir o f mandibles found i n a coyote s c a t, and by
tra c k s and feeding sign in w in ter.
Other rem ains.were id e n tif ie d w ith th e a id o f v ario u s members
o f the s t a f f and by comparison w ith c o lle c tio n s .
Numbers were determined
by te e th , head cap su les, and id e n tif ia b le bones as f a r as p o s s ib le .
The
presence o f S ilp h id b e e tle s would in d ic a te the probable e a tin g o f c a rrio n .
F eath ers, p la n t m a te ria l and extraneous substances were recorded as
"occurrence" as th e re was no way of determ ining numbers rep resen ted by th is
- 36m a te ria l.
A small amount o f g rass o r straw was found in almost every
sc at and p e ll e t analyzed; in stan c es noted in ta b le s were unusual cases.
T abulating p e ll e t and sc a t contents by occurrence only i s often
m isleading; i t gives a fa ls e p ic tu r e o f the Importance of v arious food
item s in the d ie t.
The average number of item s p e r sc a t or p e l l e t i s a
b e tt e r index o f th e q u a n tita tiv e importance o f th a t food.
A ctually mice probably c o n s titu te d over go p e r cent o f th e bulk
o f th e d ie t o f th e p re d a to rs here discussed.
D irlng th e summer the mice
were a v a ila b le to a l l o f th e p re d a to rs a t a l l tim es o f day and n ig h t.
In
w in ter t h e i r reduced a v a i la b i li t y seemed to decrease th e number taken,
b u t lo s s of o th er prey species served to in c re a se the percentage of mice
in the p re d a to rs ' d ie t.
The sharp red u ctio n in numbers o f mice in th e summer o f 19^0
d id not produce an ap p reciab le change in the food h a b its o f th e p re d a to rs
on the a re a .
This observation does not bear out the statem ent by Cottam
and Nelson (193S) th a t "shortage o f a p re fe rre d food sp ecies may be
r e f le c te d immediately in the food h a b its o f an animal and lo c a lly a l t e r
h is economic s ta tu s " .
When a v a ila b le , in s e c ts were taken in la rg e q u a n titie s by a l l
the p red a to rs on the a re a .
In coyote sc a ts and hawk p e l l e t s in s e c t
remains were found in one out o f every four o r fiv e summer specimens analyzed.
The owls took fewer in s e c ts but t h i s food s t i l l played a s ig n ific a n t ro le
in t h e i r d i e t .
B irds were taken by a l l the p re d a to rs mainly in th e
w in ter months.
This in d ic a te s th a t b ird s were preyed upon mainly i n p e rio d s
when o th e r prey was scarce.
The b ird s taken were m ostly small b ird s ,
-
pro'bably sparrows.
37-
M iscellaneous item s included such th in g s as sand,
in te r n a l p a r a s ite s , and cru stacean s.
Some extraneous m a te ria l was
found in almost a l l sc a ts and in a la rg e number of p e l l e t s .
SDMMAKT AHB conclusions
1) In an in te n s iv e ly worked, w ell populated farm are a th ese p red a to rs
prey only in c id e n ta lly on domestic anim als.
2) Bata were in s u f f ic ie n t to determ ine whether change in the number of
food item s p er c a s t was & normal seasonal flu c tu a tio n or n o t; i . e ,
whether th ere was a s ig n ific a n t v a ria tio n in th e numbers o f a sp e c ific
food item p e r c a s t a t various seasons o f the y ear.
3) Mice were th e s ta p le food o f a l l the p re d a to rs on th e study a re a
re g a rd le ss o f th e d e n sity o f mouse p o p u latio n s.
4) In s e c ts played a s ig n ific a n t ro le in the d ie t of a l l p re d a to rs.
5) B ird s, as p rey, were s ig n ific a n t but not im portant item s i n th e
predators* food.
6) Reduction o f mice may have caused a red u ctio n in the number o f
predators* perhaps p red a to rs did not change food h a b its to meet a
lo c a l shortage in t h e i r p re fe rre d food but changed hunting a re a s.
7) P red ato rs eat what i s most a v a ila b le ; the p ro p o rtio n o f food item s
in the d ie t i s p ro p o rtio n a l to th e a v a i la b i li t y o f th e prey sp ecies.
8) The p red a to rs on th is a re a had l i t t l e e ffe c t on normal prey p o p u latio n s.
LimtAlUBS CITED MD CONSULTED
Adams, Charles C, 1925. The conservation, o f p red ato ry anim als.
Mamm.6:83-96.
Jour.
B ailey, Vernon and Florence M. B ailey . 1918. Wild anim als of S la c le r
N ational Park. U .S .D .I., N at1I Park Service.
B reckenrldge, W. J . 1938. A review o f p re d a to r c o n tro l.
12; n o .10, e n try 15669.
B io l. A b stracts
Cahalane, V ictor H. 1939« The evolution o f p re d a to r c o n tro l p o lic y in
th e n a tio n a l p a rk s. Jo u r. W ild life Mgmt. J : 229-238.
Cottam, C. and A. L. Nelson. 1938. Ihy study th e food o f fu r animals?
Trans. Third North Am. W ild life Confer*, Am. JS lld life I n s t . ,
Washington, D»C., pp 527-531»
DeYoung, William and L. H. Smith. 1931* Soil survey o f th e G a lla tin
V alley are a, Montana, 1931« U .S.D.A. Bui. n o .l6 , s e rie s 1931
Djnnond, J . B.
1939• The study o f animal p o p u latio n s.
1939. Vol. 12:12. .
W ild life Beview,
E rrington, P.L .
1935. Over p o p u latio n s and p re d a tio n ; a f i e l d of
sin g u la r prom ise. Condor 371230-232.
1936. What i s th e meaning of predation?
Smithsonian I n s t . , p p .243-252.
<
Annual Beport
1938. The Great Homed Owl as an in d ic a to r o f
v u ln e ra b ility o f prey p o p u latio n s. Jo u r. W ild life Mgmt.
2:190-205.
Henderson, Junius and E. L. C raig. 1932. Economic Mammalogy.
Chas. Thomas, S p rin g fie ld , 111. 397 pp.
Leopold, Al do.
1933* Came Management.
481 pp.
Chas. S crihners Sons, New York.
McAtee, W. L.
1932. E ffectiv en ess in n a tu re o f the s o -c a lle d p ro te c tiv e
ad ap tatio n s in th e animal kingdom, c h ie fly as in d ic a te d hy
th e food h a b its o f N earctic b ird s . Smithsonian Ml sc.
C o lle ctio n s, v o l. 85, no. 7, p u b lic a tio n 3125, P 144,
Smithsonian I n s t i tu t i o n , Washington, D.C.
-3 9 -
M ills , H. B.
1937. Some Montana b ird s ; t h e i r r e la tio n to in s e c ts and
rodents, C ir, 151. Mont. Agr. Exp. Sta.
P ip e r, Stanley E. I 909. The Nevada mouse plague of 1907-08.
Farmers' Bui. no. 352.
U.S.D.A.
Table VTe Summary o f w eather c o n d itio n s In th e G a lla tin V alley during th e p erio d o f
In v e s tig a tio n . From Montana S ta te Chemistry Experiment S ta tio n w eather r e p o r t.
P r e c ip ita tio n
Snow f a l l
Snow dep th , l a s t
week o f month
1.00 1.98 1.22
1.50 27.50 22.25
J lv
82.3
52.1*
67.3
1.28
9.50
3.33
1.38
2.99
.61
SW
SE
SE
E
SE
5.00 lll.OO 13.00
SE
Wind d ir e c tio n
Monthly ave.
tem peratures
.05
1.00
191*0
Je
Feb
Mch Apr May
33.7 1*5.2 51.9 68.3 74.5
15.9 26.7 30.9 1*1 .1* 1*7.0
21*. 8 36.1 1*1J* 5U.8 60.8
SW
SB
191*0
Sep
Oot
Auk
max 82.0 70.1 60.5
min 50.0 1*5.8 36.7
ave 66.3 57.9 1*8 .6
P re c ip ita tio n
Snow f a l l
Snow depth, l a s t
week o f month
.1*5 2 .1*8 I .05
Wind d ire c tio n
SE
SE
SE
SW
Nov Deo
34.9 37.4
14.1 18.6
24.5 28.0
Jan
33.7
13.3
23.5
1.25 1.11
22.20 11.73
.20
6.78
3.10 11.00
2.00
SE
WW
SE
1941
Mch
Feb
36.3 4 6 .6
15.8 25.9
26.3 36.3
•44
8.50
♦78
3.60
WW
SE
E
-OtT-
Monthly ave.
tem p eratu res
max
min
ave
19!59
Nov Dec
Jan
52.5 1*0.6 23.8
25.1* 22.5
3.3
58.9 51.7 13.5
41
HllMAy 191
WH-ST
; WH-ST
P
OATS M J r \
W-WH
WH-ST
ALF
WH-ST
HAY
ALF
WH-ST
M AP
OF
IRRIGATION
--------- ■'-*
« 0
DITCH
STREAM
INTERMITTENT
STRA W PILE
ST REA M
C 22b
STACK
w il l o w -a l d e r
m
D o
COTTONWOOD
T RE E S
F A R M BUILDINGS
“ ea
W-WH
W-WH
HAY
/93 9-40
1940-41
I / WH-ST
ALF
f )0 L 0 ST
THE STU D T AREA
A REA - /
— ___ ^
ALF
SO. MILE
WH-ST
WHEAT
r -F L
FALL
W-WH
ALF
p
WINTER WHEA T
ALFALFA
PA S T U R E
OATS
HAY
OATS
NIXED
POT
POTATOES
GAP
GARDEN
brush
CROP
CROP
P late I
STUBBLE
<.
PLOWING
GRASS ES
*
i
CLOVER
Plate II. Graphic suggestion of predator-pressure and prey-availability. Arbitrary, but
proportionally significant values used to indicate predator-pressure and prey-availability at
different times of the year.
Ic-wov
Predators
Eutec lagopus s-jnhannis
Buteo borealis calurus
Circus hudsonius
Bubo virginianus occ.
Canie latrans
Mustela longicauda
Felis domeStious
Mephitis hudsonius
K3
re
CS
EZ)
S3
E5S
A v a ilability of all
prey except nice
Prev
P h a s ianus colchicus tor.
P erdix p. p e rdix
Lepus townsendi
Citellue richardsonii
Micr o t u s epp.
Peronyscus sp
as
CS
BI
(cyclic regress
C23
Dec-Feb
'.'ch-May
beP-Nov
Dec-Feb
Md
I
T
P la te I I I
F ig u re I .
C oyote s c a t .
-
F ig u r e 2 .
The same s c a t a n a ly z e d ; b o n e s end f u r o f l l i c r o t u s .
U pper l e f t : fra g m e n ts o f b o n e s .
U p p er r i g h t : f i v e u p p e r - l e f t i n c i s o r s ,
s e v e n u p p e r - r i g h t i n c i s o r s , and a p a i r
i n th e m a x i l l a e ,
fiv e lo w e r-le ft in c is o rs ,
s ix lo w e r-rig h t i n c is o r s .
C e n te r : b i t s o f g r a s s .
B o tto m : f u r .
-4 4 -
P la te H i
P l a t e IV
F ig u r e I .
Hawk p e l l e t s .
F ig u re 2 .
The l a r g e r p e l l e t a n a l y z e d ; b o n e s and f u r o f H l c r o t u s .
U pper l e f t : b o n e f r a g m e n ts .
Top c e n t e r : two p a i r s o f u p p e r i n c i s o r s .
U pper r i g h t : two p a i r s o f lo w e r i n c i s o r s .
b e lo w : s k u l l w ith f u l l com plem ent o f i n c i s o r s .
C e n te r l e f t : b i t s o f g r a s s .
C e n te r r i g h t : b i t s o f e x o s k e le to n o f a g r a s s h o p p e r .
B o tto m : f u r .
F ig u re 3 .
Owl p e l l e t s .
F ig u r e 4 .
The l a r g e s t p e l l e t a n a l y z e d ; b o n es and f u r o f ! 'l c r o t u s .
U p p er l e f t : f r a g m e n ts o f b o n e s , t a i l , and f o o t .
U pper r i g h t : s k u l l w ith u p p e r i n c i s o r s and tw o p a i r
o f upper in c is o rs .
b e lo w : m a n d ib le s w ith i n c i s o r s , t h r e e l o w e r - r i g h t
i n c i s o r s and two l o w e r - l e f t i n c i s o r s .
C e n te r: b i t s o f g r a s s .
B o tto m : f u r .
-4 6 -
P l a t e IV
APPENDIX
T ab le V I I .-—R e s u lts o f a n a ly s is o f c o y o te s c a t s tak en betw een O ctob er, 1939» &&& A p r il, 19^1 •
FALL 1939
32. 4 mice, I Nematoda, chicken fe a th e rs
1. 8 mice
33. 7 mice, se v e ra l tapeworm p ro g lo ttid s
2. 3 mice, canine o f small carnivore,
34. 2 mice
p iec e o f com cob, g rass
35. 2 mice, 2 la rg e p ie c e s of wood
3. 6 mice, I sm all gastropoda
36. 6 mice
4. 3 mice
37. 4 mice
5. 3 mice
38. I mouse
6. 3 mice
. I mouse
7. 2 mice
. 2 mice, forb leaves
8 . I mouse, 3 A crid id a e , I D iptera
41. I mouse, small b ir d fe a th e rs
9 . 2 mice, I A crididae
42. 7 mice, I sm all b ir d
10. 6 mice
43. 3 mice
11. 4 mice, stone l/4 " diam eter .
44.
8 mice
12. 2 mice
45. 4 mice
13. 3 mice, long blade of "slough grass"
4b. 5 mice
14. 5 mice
'
47. 4 mice
15. 5 mice, g ra s s, Hordeum seeds
48. I mouse, considerab le fin e g rass
16. 4 mice
49. 5 mice
- 17. 2 mice
50. 4 mice
IS. 4 mice
51.
4 mice
19. 2 mice
52.
2 mice
20. 9 mice
53.
6
mice
21. 9 mice, I Scarabaeidae
22. 4 mice
JSPRINSr 19^0
23. 6 mice
54. 4 mice, 6 pupal cases
24. 4 mice
55 . 5 mice, 2 Acrididae
25. 5 mice, 4 Coleoptera, I Lepidoptera
56. 3 mice, sm all b ird fe a th e rs
5 blow fly larvae, carrion C itellu s
57 . 6 mice, I Acrididae, sn a il bird feathers
richardsonll,
58. 4 mice, 34 blades o f "slough grass"
26. tS m ice. I A crid id ae, grass and leav es
59. 7 mice, Poa l eaves and seeds
27. 3 mice
60.
4 M lcrotus, I Peromyscus
28. 3 mice
61.
7 mice, I A c rld idae
29. I mouse
62. Mouse h a ir , la rg e amount o f d i r t
63. 8 mice
WINTER 1939-1(0
64. Only mouse h a ir
30. 3 mice
31. 4 mice
T ab le VII continued.___________
65. 6 mice, sm all b ir d fe a th e rs ,
ra b b it f u r
93. 3 mice
94. 3 Bice
WINTER '1940-41
SUMMSE 1940
3 mice
66 . 2 mice
9 l 5 mice
67. 6 mice
97. 5 mice 1
68 . 5 mice
69. 2 mice, 2 A crididae, I Lepldoptera la rv a 98. 3 mice
99. 6 mice
70. 2 mice
100 . 2 mice
71. 5 mice
mice
101 .
102
.
mice, 72 inches o f g rass leaves
FALL 1940
103. 4 mice
72. 10 mice, sm all white b ir d fe a th e rs
104. 5 mice
3 mice
105. 8 mice
8 mice
106. 2 mice. b i l l and fe a th e r stub
3 mice
of p a rtrid g e
76*. 3 mice
77. 3 mice, much fin e straw end grass
SPRING 1941
78. 9 mice, 1 Nematoda
107. Only mouse h a ir
___
79. 5 mice, 2 Nematoda
108. 3 mice
mice, wheat straw and ch aff
SO.
109. 2 mice
mice
81.
HO. 2 mice
82. 4 mice
111. I mouse
85. 3 mice
112. 2 mice
86 . 7 mice, 2 Acrididae, I Nematoda
87. 3 mice, 31 Noctuidae la rv a e , 2 Carabldae
2 Sylphidae
88 . I mouse
89. 5 mice, I A crid id ae, I C occlnellidae
90. 6 mice, I D iptera
91. 3 mice, I A crididae
92. 3 mice, 64 Carabidae, 2 Noctuldae la rv a e ,
sm all white b ird fe a th e rs
1
Jfc
T able V I I I . — R e s u lts o f a n a ly s is o f hawk p e l l e t s ta k e n "between O c to b er, 1939 s n ^- A p r il, 19^1«
FALL 1939
29. 2 mice
1. 3 mice*
30. 3 mice, se v e ra l leav es o f forbs
2. 3 mice
31. I mouse
3. 6 mice, I Hemiptera
32 . I mouse, I Hemiptera
4. 2 mice
33. 4 mice
5. 2 mice
34. I mouse, Lepus towsend! h a ir
6. I mouse
35. I mouse, I Coleoptera
7. I mouse
36. I mouse, I A crid ld ae. I small b ird
g. I mouse
fe a th e r
9. I mouse
37 . I mouse
10. 3 mice, I AcridiAae
33.
I mouse, 2 Coleoptera
11. 2 mice, I AcridiAae
39.
(p a rts of 7 p e lle ts ) " 11 mice, I A cridldae
12. I mouse, I A crididae
40.
(p
a rts of 5 p e ll e t s ) 10 mice
13. I mouse
14. 3 mice, I A crididae
Wmnm i 939J <o
15. 3 mice, I A crididae
41. 1 mouse
16. Only mouse h a ir , 3? inches of grass
42. 3 nice
17. 2 mice, I A crididae
4 3 . 5 mice
18. 2 mice
44. 3 mice
19. I mouse
45. I mouse
20. 3 mice, 2 A crld ld ae, I Coleopter^ la rv a ,
46. 3 mice
2 k e rn e ls o f wheat, I o f o ats
47. I mouse
21. 2 mice
43. 3 mice
22. 2 mice
49. I mouse
23. 2 mice
50. 2 mice
24. 2 mice
51. 4 mice
25. 3 mice, I C oleoptera
52. I mouse
2o. 3 mice
53. I mouse
27. 2 mice
54. 2 mice
23. 2 mice
♦ P e lle t numbers have no seq u en tial sig n ific a n c e , they are only f o r convenience.
A ll mice id e n tif ie d were e ith e r M lcrotus pennsylvanicus modestua o r M. Panusli
TABLE> 1 1 1 OontiguejL
SPRING 1940
69. 2 m ice, I Elaterida-g,. straw ,
p a rts o f se v e ra l wheat k ern els
70. 2 m ice, wheat straw
71. I mouse
72. I mouse
73. 2 m ice, wheat straw
74. 4 m ice, I a n t
75. 2 mice
76. 2 mice
77. 5 mice
78. 3 mice
79. 3 mice
80. I mouse
81* 2 mice
82. 2 m ice, I a n t, 2 b i t s o f send
83. I mouse, I A arldidae
84. 3 m ice, 5 Noctuldae la rv a e
85. 5 mice
86. I mouse
87. I mouse
88. 3 mice
89. 2 mice
90. 2 mice
91. I mouse
92. 5 mice
93. 5 mice, I Coleootera
94. I mouse
95. 2 m ice, piece of wood -g x I"
96. 2 mice
97. 3 m ice, canine o f sm all carnivore
98. 2 mice
99. 2 m ice, 3 Coleootera
100. 2 m ice, numerous sm all b ir d fe a th e rs
SUMMER 1940
„ .v
101. 3 m ice, numerous sm all b ir d fe a th e rs
102. 5 mice
103. 4 mice
104. 4 mice
105. 2 mice
106. I mouse
„
107. I mouse, 6 Silohidae,. I sm all fe a th e r
108. 2 m ice, 5 s<^ rah/aeid aa.
109. 2 m ice, I C o le o o te riL
H O . 3 mice
111. 4 mice
112. 5 mice
113. I mouse, C ite llu # Th cfrardsonil h a ir
114 . only mouse h a ir
115. I mouse
116. only mouse h a ir
-IS -
55* I mouse
56. I mouse
57. 2 mice
58* I mouse
59. U mice
60. I4. mice
61. 3 mice
62. I mouse
63* 3 mice
64. 2 m ice, c o n sid erab le straw
65* 4 mice
66. I mouse
67. 4 mice
68. 2 mice
- IABLE V I I I c o n tin u e d
117. mouse h a i r , C ite llu s rlo h a rd so n ll h a ir
one sm all fe a th e r
118. I mouse, I El a t e r l d a e , I Scarabaeidae
.
119. I mouse
120. I mouse, I S jlp h id ae
121. 3 mice
122. I mouse, 3 C oleoptera
123. I mouse
124 1 mouse, 2 C oleoptera
•
125. 2 mice
126. only mouse h a ir
127. I mouse
128. I mouse, I A orididae
129. I mouse, I A crldidae
130. 6 m ice, I C oleoptera, I A crididae
131. I mouse
132. I mouse, 2 Coleoptera
133. I Thom/bmys ta lp o ld e s , mouse h a ir
134. 2 mice
135. 1 mouse
136. 2 mice
137. only mouse M i r
138. 1 mouse
139. 2 mice
140. I mouse
141. 1 mouse
11*2 . 2 mice
143. 3 mice
A orididae
144. I mouse, I __________
I
mouse
145.
146. I mouse, 3 A crididae
147. 1 mouse
148. 2 m ice, I Coleoptera la rv a
149. I mouse, I A crididae
.
150.
151.
152.
1 53 »
154.
155.
156.
157.
2 m ice, I A orididae
3 mioe
I mouse, I Acrididae, I Coleoptera larva
I mouse, 5 Acrldidae
2 m ice, 2 A crididae
2 m ice, 2 A c r id id a e
(parts of 7 p e lle t s ) 7 mice
2 m ice, I A orididae
FALL 1940
'
158. I mouse, I C oleoptera
159. I m o u se. I N o o tu id a e la r v a . I
Mallophaga. I head Soirpus
160. 2 m ice, I C oleoptera
161. 2 m ice. I C oleoptera la rv a
162. I mouse, I CoocineiTldae
163* only mouse h a ir ,
164* mouse M ir , I Carabidae
165. I mouse, 2 C oleoptera
166. mouse ftir, I A orldidae
167. 2 mice
168* 3 mice
169* 2 m ice, I C oleoptera la rv a
170. mouse M i r , I A orldidae
171. I mouse, I A c rid id a i
172. 2 m ice, I A crididae
175» 2 m ice, 4 A c r id id a e
174« 2 mice
U 7 5 » 2 mice
. 176. I mouse, I C ite llu s ric M rd s o n ll
177. 2 mice
178. I mouse
179. 2 m ice, I A crid ld ae, 10 seeds Heliaxrthus,
.16 g sand
-TABLE V I I I co n tin u ed
one sm all fe a th e r
118. I mouse, I El a t e r i d a e , I Scarahaeidae
119» I mouse
120. I mouse, I S jlp h id ae
121. J mice
122. I mouse, 3 Coleoptera
123* I mouse
——— ———
12U. I mouse, 2 C oleoptera
125. 2 mice
126« only mouse h a ir
127» I mouse
128. I mouse, I A orididae
129» I mouse, I Acrldidae'
130. 6 m ice, I C oleoptera, I A crldidae
131. I mouse
132. I mouse, 2 Coleoptera
133. I Thom/omys ta lp o ld e s , mouse h a ir
13&* 2 mice
135* I mouse
136. 2 mice
137. only mouse M i r
138. I mouse
139* 2 mice
1^0. I mouse
I i t l . I mouse
lit2 . 2 mice
114.3« 3 mice
Iijit, I mouse, I A erldidae
IitS. I mouse
lit6 . I mouse, 3 A crldidae
lit?* I mouse
II48. 2 m ice, I Coleoptera la rv a
lit9« I mouse, I A crldidae
150.
151.
152.
153*
ISU.
155»
15o«
157«
2 m ice, I A crldidae
3 mice
I mouse, I A crld id ae, I Coleoptera la rv a
I mouse, 5 A crldidae
2 m ice, 2 A crldidae •
2 m ice, 2 A crldidae
(p a rts of 7 p e l l e t s / 7 mice
2 m ice, I A crldidae
FALL 19ltO
158. I mouse, I C oleoptera
159. I mouse. I Kootuldae la r v a , I
Mallophaga. I head Soirous
160« 2 m ice, I C oleoptera
161* 2 m ice. I C oleoptera la rv a
162. I mouse, I C o ccin eilid ae
163* only mouse h a ir ,
I 6it. mouse h a i r , I Carabldae
I 65. I mouse. 2 C oleoptera
166* mouse f u r , I A crldidae
167« 2 mice
168. 3 mice
169* 2 m ice, I C oleoptera la rv a
170. mouse h a ir , I A crldidae
171. I mouse, I A crididaS
172. 2 m ice, I A crldidae
173* 2 m ice, It A c r ld id a e
174« 2 mice
■175« 2 mice
. 176. I mouse, I C ite llu s rlc h a rd so n il
177* 2 mice
178» I mouse
179. 2 m ice, I A c rld id a e, 10 seeds B e llan th u s,
•16 g sand
-3 5 -
117 . mouse h a ir , C lte llu s rlchardsonil h a ir .
rTAELE T i l l c o n tin u e d
180#
181*
182*
183#
18U#
183»
186#
187*
188*
189»
190*
191»
192.
193#
1%.»
195*
196#
197*
2 m ice, I A crldldae
2 mice
J mice
3 mice
I mouse
3 mice
2 mice
2 mice
I mouse
I mouse
2 m ice, 2 C oleoptera, I A orididae*
6 g rain s o f o a ts
2 mice
I mouse
3 mice
I mouse, I sm all "bird fe a th e r
2 mice
only mouse h a ir
I mouse, se v e ra l small b ir d fe a th e rs
198*
199«
200*
201*
202.
203*
2QU*
205*
206*
207*
208*
209*
210.
211*
212.
I
I
I
I
2
I
I
I
3
I
2
3
2
I
I
3
mouse
mouse
mouse, I S ilp h id a e , I Carabidae
mouse
— ———
mice
mouse
mouse, I A crid id ae, I Sylphidae.
Coleoptera
mice
mouse
mice
mice
m ice, I sm all b ird fe a th e r
mouse
mouse, I A crldidae
mice
TABLE IX .
R e s u lt s o f a n a ly s is o f owl p e l l e t s ta k e n b etw een O c to b er , 1 9 3 9 , and A p r i l , 19^1•
FALL 1939
1 . 3 mice
2 . 3 m ice, I chokecherry p i t
3 » 5 mice
Iu I mouse
5 « I mouse, I sm all b ird fe a th e r
6. 2 mice
7 * I mouse, 2 sm all b ird s
8 # 3 mice
9 « I mouse
10* 3 mice
11* 2 mice
12. I* mice
13» 3 mice
lit* 3 mice
15* it m ice, head of Compositae
16* 2 mice
—— — —
17» I mouse
18, I mouse, 1*1; g sand* Elymus glumes
19* 3 m ice, 10 A crid id ae* I C oleoptera*
7 k e rn e ls o f wheat
20* 2 mice
21* 2 m ice, 5 C oleoptera, 2 A crldidae
22* 2 mice
23* I mouse, 2 A orididae
2k* I mouse
23. 3 mice
26* I mouse
27» I mouse, 2 Noctuldae larv a e
28* 2 m ice, 2 C oleoptera, I A crldidae
29» 3 mice
30» mouse h a i r , it C oleoptera, g rass glumes
31* 3 m ice, I Coleoptera
WINTER 1939-kO
32* I mouse
33* I mouse
3k» I mouse
35* 2 m ice, la rg e amount o f g rass
36» I mouse
37» 2 mice
38. I mouse
39* 2 mice
kO* I mouse
I t l • I mouse, se v e ra l small b ird fe a th e rs
2t2* 2 mice
ll3* I mouse
ltk* 2 mice
it5* 2 mice
2t6* I mouse lt7* 2 mice
it8* I mouse
lt9* I mouse, g ra ss glumes
50» I mouse
51» 2 mice
52, I mouse
SPRING 19kO
53* 2 mice
54* I mouse, I Sorex
55* 2 mice
56* I mouse, 7 k e rn e ls o f w heat, I stone
. 57* I mouse
58* it m ice, straw
.
59* it m ice, p iece o f wood
60. 5 mice
61* 2 mice
TABLE IX c o n tin u e d
62.
63.
64.
65.
66.
67.
6S.
69.
70.
71.
72.
73»
74.
73.
76.
77.
78.
79.
80.
7
5
2
3
4
I
2
I
I
I
6
I
9
I
I
I
3
6
4
mice
mice
mice
mice
mice
mouse
mice
mouse
mouse
mouse
mice, 2 In s e c ta
mouse
m ic e , 3 l a r g e C o lc o p te r a , I D iptera
mouse
mouse
mouse
mice
mice
mice
SUMMER 19^0
81. I mouse
82. 2 mice
S3. I mouse
84. 2 mice
.
85.
I m ouse, I I mm. p a r t r i d g e
86.
87.
88.
89.
90.
I
I
I
I
I
mouse
mouse
mouse
mouse
mouse
FALL
:9 i.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
1940
I mouse, sev era l sm all fea th e rs
5 mice
I p a rtrid g e
I mouse
I mouse
I mouse
I mouse
5 mice
I mouse, I A crididae
2 mice
I mouse
3 mice
2 mice
3 mice, I C ite llu s rlc h a rd so n li
WINTER 1940-41
105. I mouse
106. 2 mice
107. I mouse
108. 3 mice
109. 2 mice
HO. 4 mice
111. I mouse
112. I mouse
113. 3 mice
114. 2 mice
115. I mouse
116. I mouse
R e s u lts o f a n a ly s is o f o th e r s c a t s ta k e n betw een O cto b er, 1939 and. A p r il, 19U l.
SKUHK
1. 5 mice
2. 3 mice
3. I mouse
U. I mouse
5. I mouse
6. I mouse, U A crld ld ae, 2 Coleoptera
7. - .e n t i r e l y C o le o p te r a , A c r ld ld a e
g.
e n t i r e l y C o le o p te r a , A c r i d id a e
9.
2 mice, much f in e ly cut g rass and straw
W2ASEL
1. mouse h a ir
2. mouse h a ir
3.
4.
5.
6.
7.
g.
9.
10.
11.
12.
13.
14.
15.
16.
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
mouse
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
h a ir
-95”
X.
Area*
D ate s
Eame:
Species
Tracks
Heard
Den,' i Location
nest I '
Scats
Feeding sig n • C arcass,
k ille d by P e lle ts
I
Location
M iscellaneous
d u st b a th s , form s, h air,
fe a th e rs, etc-
/
*
:
z.
3.
•
4.
i. ‘
-
5.
6. ______________
■■
*1__________ __
8.
•:
9.
10.
•
IlIt
'. ' -
13.
/♦.
/5.
*
-
/6
It
/8.
...
-
■-
-
1
-
.'
.
D a te :
W e a th e r:
S p e c ie s
Name,
warm, u su a l, c o l d , tem p._____
s u n n y , c l o u c y , r a i n y , snoiving
w in d y , b r e e z y , g u s t y , s t i l l
Number
Time
L o c a tio n
. T im lin f i e l d
F r o m ______
F lu s h e d
d ir d is t
G e n e ra l c o v e r
s lo p e ; d i s t , d i r t o c o v e r
A re a ;
G round:
E x a c t COT.
D ry , dam p, w e t, f r o z e n , snow
S e ttle d
D ir d i s t co y
R e f lu s e d
d is t d ir
R e s e ttle d
d i s t cover