Waterfowl relationships to Greenfields Lake, Teton County, Montana
by Leroy J Ellig
A THESIS Submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree
of Master of Science in Fish and Wildlife Management
Montana State University
© Copyright by Leroy J Ellig (1953)
Abstract:
A study of waterfowl relationships to Greenfields Lake, Teton County, Montana, was conducted May 9
to November 30, 1951 and May 28 to September 20, 1952. Information on spring migration was
obtained during week-ends in March, April, and May, 1952 Territorial pairs and lone males were
censused to determine breeding population. A nesting study was conducted both years. An experiment
on the effect of skunk control upon success of nests was carried out in 1952. Brood observations were
made in 1951 and 1952. Information on hunter utiliz ation and success was secured during the 1951
hunting season. WATERFOWL RELATIONSHIPS TO GREENFIELDS LAKE,
TETON COUNTY, MONTANA
by
LEROY J . ELLIG
A THESIS
S u b m itted t o th e G raduate F a c u lty
in
p a r t i a l f u l f i l l m e n t o f th e re q u ire m e n ts
f o r th e d egree o f
M aster o f S c ie n ce i n F is h and W ild lif e Management
at
Montana S ta te C o lleg e
Approved:
a
M P ir /.
He^o^ M ajor D ^ a ^ tm e n t
Cl .
Chairm an, Examining^Committee ^
le a n ,' G raduate D iv is io n
I
Bozeman, Montana
May, 1953
S *
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*
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y
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2-
E A S S m-
TABLE OF CONTENTS
Page
A b s tra c t ....................................................................................................................
3
I n tr o d u c tio n ............................................................................................................
b
D e s c rip tio n o f a r e a ............................................................................................
L
S p rin g m ig ra tio n ...................................................................................................
12
B reeding p o p u la tio n ..................................
16
N e stin g s t u d y ..............................
19
Methods ..............................................................................
19
N e stin g c o v e r ...............................................................
23
F a te o f eggs and n e s ts ...........................................................................
2£
Broods ..............................
36
H unting s e a s o n ................................................................................
UO
Sum m ary............................................................................
Wi
L i t e r a t u r e c i t e d .......................................
W>
106720
-3 -
ABSTRACT
A s tu d y o f w a te rfo w l r e l a t i o n s h i p s to G re e n fie ld s L ake, Teton
C ounty, M ontana, was conducted May 9 to November 3 0 , 1931 and May 28
to Septem ber 20, 1932. In fo rm a tio n on sp rin g , m ig ra tio n was o b ta in e d
d u rin g w eek-ends i n M arch, A p r i l , and May, 1932. T e r r i t o r i a l p a i r s
and lo n e m ales were cen su sed to d eterm in e b re e d in g p o p u la tio n . A
.n e s tin g s tu d y was conducted b o th y e a r s . An ex p erim en t on th e e f f e c t
o f skunk c o n tr o l upon su c c e ss o f n e s ts was c a r r ie d o u t in 1932. Brood
o b s e rv a tio n s were made i n 1931 and 1932. In fo rm a tio n on h u n te r u t i l i z
a tio n and su c c e ss was s e c u re d d u rin g th e 1931 h u n tin g se a so n .
—)I—
INTRODUCTION
The c o n s ta n tly d im in is h in g number o f s u ita b le w a ter a re a s i s one o f
th e m ajor co n cern s o f w a te rfo w l management th ro u g h o u t th e U n ite d S ta te s
(Day, 195>0) .
Thus th e p ro p o sed d ra in in g o f G re e n fie ld s Lake ( a ls o known
as F re e z e o u t Lake) i n Teton C ounty, n o r t h - c e n t r a l Montana, by l o c a l groups
to a l l e v i a t e in u n d a tin g o f a g r i c u l t u r a l la n d s and w aterfo w l crop d ep re­
d a tio n s cau sed c o n s id e ra b le concern to th e Montana F is h and Game D e p art­
m ent.
A s tu d y to d eterm in e w aterfo w l r e l a t i o n s h i p s to th e a re a was con­
d u c te d ' May 9 to November 3 0 , 19!?1 and May 28 to Septem ber 20, 1952.
In ­
fo rm a tio n on s p rin g m ig ra tio n was se c u re d d u rin g w eek-ends i n March,
A p r il, and May, 1952.
The w r i t e r i s g r a t e f u l to th e Montana F is h and Game D epartm ent f o r
fin a n c in g th e s tu d y ; to w a terfo w l b i o l o g i s t s % nn Freeman f o r s u p e rv is io n
and G erald S a lin a s f o r encouragem ent and a s s is ta n c e i n f i e l d work; to
o th e r p e rs o n n e l and s tu d e n ts o f Montana S ta te C o lleg e who a s s i s t e d i n n e s t
s e a rc h e s ; to D r. ¥ . E. B ooth, Montana S ta te C o lle g e , f o r v e r if y in g i d e n t i ­
f i c a t i o n o f p l a n t s ; s in c e r e a p p r e c ia tio n i s ex ten d ed to D r. Don C. Qpimby,
Montana S ta te C o lle g e , f o r advice and s u p e r v is io n d u rin g th e s tu d y and
p r e p a r a tio n o f th e m a n u s c rip t.
DESCRIPTION OF AREA
G re e n fie ld s Lake i s lo c a te d on th e w e ste rn edge o f th e G re e n fie ld s
D iv is io n , Sun R iv e r I r r i g a t i o n P r o j e c t , a p p ro x im a te ly 2 m ile s n o rth w e st
o f F a i r f i e l d ; M ontana.
I t o c cu p ie s th e lo w er p o r tio n o f a g l a c i a l la k e
b e d , b a se e le v a tio n 3 ,6 5 b f e e t , w ith no n a t u r a l o u t l e t .
Long, s lo p in g
p la te a u s , w ith e le v a tio n s o f a p p ro x im a te ly I+,000 f e e t , encompass th e
b a s in (G ie s e k e r, 1937)•
The la k e was n o t a perm anent body o f w a te r p r i o r to i r r i g a t i o n o f
su rro u n d in g a r e a s , i n i t i a t e d i n 1919 (DeYoung, 1 9 2 7 ), and in c re a s e d to a
maximum o f 6.8,314-7 a c re s by 19k!? (B ur. B e c ., 1931)•
R e s id e n ts r e p o r t t h a t
p r e v io u s ly th e s p rin g r u n o f f g e n e r a lly d r ie d up d u rin g th e summer, b u t in
"w et yeans" some w a te r was r e t a i n e d .
th e la k e was d ry .
N in e te e n -tw e n ty was th e l a s t y e a r
I n I 9I4I i t cov ered 1,900 a c r e s , by 1932 i t had i n ­
c re a s e d >to U,100 a c r e s w ith a maximum d e p th o f 9 .6 f e e t and a s h o r e lin e
o f 21.88 m ile s .
The in c r e a s e in s iz e a p p a r e n tly r e s u l t e d from w aste and
seepage w a te rs flo w in g in to th e la k e v ia 10 d itc h e s from a d ja c e n t i r r i ­
g a te d la n d s a n d /o r above average p r e c i p i t a t i o n d u r in g '1939 to 1931 (see
b e lo w ).
The la k e s u p p o rts abundant grow ths o f submerged v e g e ta tio n , m o stly
sago pondweed (Potamogeto n p e c t i n a t u s ) and w ig eo n g rass (R uppia m a ritim e ) ?
. o th e rs in c lu d e horned poolm at ( Z a n n ic h e llia p a l u s t r i s ) , m uskgrass ( Chara
s p p . ) , and w a te r m i l f o i l (M yriophyllum e x a lb e s c e n s ) .
A lk a li b u lru s h •
( S d ^ u s p a lu d o su s) i s th e o n ly em ergent s p e c ie s o c c u rrin g i n q u a n t i t i e s ,
b u t s o fts te m b u lru s h (S . v a l i d u s ) , American b u lru s h (S^ am erican u s) ,
s p ik e ru s h (E le o c h a r is m acrosta c h y a ) , w ire ru s h ( Juncus b a l t i c u s ) , and
c a t t a i l ( Typha l a t i f o l i a ) a re a ls o fo u n d .
. A marsh o f 36O a c r e s , connected to th e la k e by a & m ile d ra in a g e
d itc h (Fig* I ) , p ro v id e s th e o n ly s u b s t a n t i a l s ta n d o f em ergent c o v er,
m o s tly c a t t a i l s (F ig . 2 ) , on th e a r e a .
O ther em ergent s p e c ie s in c lu d e
-
6-
LEGEND
B G fiA S S
B GREASEW OOD
[ffll AGRICULTURAL
B CATTAIL
E E IT R A P LINE
EE DRAINAGE DITCH
F ig . I .
Map o f G re e n fie ld s Lake s tu d y a r e a .
-
7-
-8 th o se above.
T nundation h as produced numerous sm a ll is la n d s i n two bays o f th e
e
la k e (F ig . 3 )•
Dominant v e g e ta tio n i s g e n e r a lly grea^wood (S a rc o b a tu s
v e rm ic u la tu s ) .
The la k e sh o re v e g e ta tio n i s m a in ly g ra s s w ith greasew ood dom inant
on a l k a l i im p reg n ated a re a s (F ig . I t) .
The greasew ood ty p e h as a hummocky
a p p ea ra n ce , th e r e s u l t o f s o i l e ro s io n betw een p la n ts (DeYoung, 1 9 2 7 ).
T his type o c cu p ie s 3 9 .0 p e r c e n t (8.3U m ile s ) o f th e s h o r e lin e (F ig . l ) .
Twenty-two 900 f o o t l i n e i n t e r c e p t s ( C a n fie ld , 19 lt2 ), each ta k e n p erp en ­
d ic u la r to th e s h o r e lin e , gave an av erag e greasew ood canopy c o v er o f l i t . I
p e r c e n t ( 2 .0 - 3 lt.lt) .
T w enty-four 300 p o in t t r a n s e c t s (C oupland, 195)0)
were ta k e n p e rp e n d ic u la r to th e s h o r e lin e to m easure ground c o v er e x ­
c lu d in g greasew ood.
A b o a rd w ith 10 n a i l s sp aced 10 c e n tim e te rs a p a r t
was p la c e d on th e ground a t 12 s te p i n t e r v a l s s t a r t i n g a t th e s h o r e lin e .
V e g e ta tio n to u c h in g th e t i p o f each n a i l was re c o rd e d .
f o r 7,200 p o in ts was 2 3 .6 p e r c e n t ( 7 .0 - 3 3 .0 ) .
Average d e n s ity
P la n ts p r e s e n t and t h e i r
p e rc e n ta g e o f ground c o v er w ere: f o x t a i l b a r le y (Hordeum jubatum ) , 2 2 .6
p e r c e n t; s a l t g r a s s (D i s t i c h l i s s t r i c t a ) , .19.35 w e ste rn w h eatg rass (Agropyron s m i t h i i ) , 11.75 Sandberg b lu e g ra s s ( Poa secunda) , 11.75 N u tta ll
s a lt b r u s h ( A trip le x n u t t a l l i i ) , 9«75 b lu e g ra s s (Poa s p p . ) , 9.15 a l k a l i
d ro p seed (Sporo b e lu s a i r o i d e s ) , 6 . 6; b lu e gramma (B outeIoua g r a c i l i s ) ,
h
e
2 . 6 ; X yssopleaf ^ c h in o p s ilo n (E e h in o p s ilo n h y s so p ifo liu m ) , 2 . 2; seepweed
( Suaeda d e p re s s a ) , 1 .8 ; p ep p erw o rt (Lepidium v irg in ic u m ) , 1 .3 ; N u tta ll
a l k a l i - g r a s s ( P u c c in e l lia n u t t a l l i a n a ) and June grass (K o e le ria c r i s t a t a ) ,
-
F ig . U.
F ig . S .
9-
T y p ic a l greasew ood c o v er which c o n s t i t u t e s 39 p e r c e n t o f
th e sh o re l i n e .
T y p ica l g ra s s c o v er which c o n s t i t u t e s
sh o re l i n e .
p e r c e n t o f th e
-1 0 1 *1 »
«
G rass c o v er (T ig . £) o c cu p ie s
s h o r e lin e (F ig . l ) .
c e n t (2 7 .0 -7 2 * 3 ).
p e r c e n t ( I I . I 46 m ile s ) o f th e
The average d e n s it y o f 6,600 p o in ts was U?.3 p e r
P la n ts p r e s e n t and t h e i r p e rc e n ta g e o f ground co v er
w ere: b lu e gramma, 5 3 .8 p e r c e n t; w e ste rn w h e a tg ra s s, 2 1. L; n e e d le g ra s s
(S t i p a com ata) , 8 . 6 ; s a l t g r a s s , 5 . 8 ; f o x t a i l b a r le y , 3 . 0 ; f r in g e d sage
(A rtem isia f r i g i d a ) , 2 .0 ; a l k a l i d ro p se e d , 1 .2 ; J u n e g ra s s , 1 .0 ; gumweed
(G r in d e lia s q u a r ro s a ) , seepw eed, h y s s o p le a f e c h in o p s ilo n , U u t t a l l a lk a li.- ■
g r a s s , r a b b i t b ru s h (Chrysotham nus n a u se o su s) , Sandberg b lu e g r a s s , snake­
weed (G u tie r r e z ia s a r o th r a e ) , U u t t a l l s a l t b r u s h , and u n i d e n tif ie d p l a n t s ,
e
3 .0 . G razing p re s s u re was c o n sid e re d heavy i n g ra s s and grea^wood ty p e s .
Monocot nom enclature fo llo w s B o o th 's (1950) F lo r a o f M ontana, P a rt X.
D ic o ts fo llo w B ooth' and W rig h t's (1953) F lo r a o f M ontana, P a r t I I .
I r r i g a t e d farm la n d s o f a l f a l f a , s m a ll g r a in s , and summer f a llo w
( F ig . 6) form 8 .6 p e r c e n t ( l . 88 m ile s ) o f th e s h o r e lin e (F ig . I ) .
The
la n d i s c u l t i v a t e d to a d is ta n c e o f 60 to 170 f e e t from th e la k e sh o re ,
depending on m o istu re c o n d itio n s .
The c lim a te i s s e m i-a r id ; average a n n u al p r e c i p i t a t i o n a t F a i r f i e l d
d u rin g 1906-1938 was 11.53 in c h e s (Maughan, 1 9U l)j f o r 1939-1951, 12.U9
in c h e s (U .-S . D ept, o f Commerce).
The months o f A p r il, May, Ju n e , and
J u ly re c e iv e 5 6 .9 per c e n t o f th e p r e c i p i t a t i o n .
f o r Ja n u a ry i s 2 1 .6 ° F . , J u ly , 65° F .
The av erag e te m p e ratu re
The average l a s t k i l l i n g f r o s t i s
May 1 9 , th e f i r s t Septem ber 20 (Maughan, 1 9 U l)«
-1 1 -
F ig . 6 .
I r r i g a t e d a g r i c u l t u r a l la n d a d ja c e n t to la k e .
o ccu p ied 8 .6 p e r c e n t o f th e sh o re l i n e .
This type
-1 2 SPRING MIGRATION
O b se rv a tio n s o f th e s p r in g m ig ra tio n w ere made b y a e r i a l f l i g h t s ,
b o a t, and on f o o t .
A 7 x 5>0 b in o c u la r and 2Ox s p o ttin g scope w ere u sed
f o r -se x in g and i d e n t i f i c a t i o n . A heavy s p r in g r u n - o f f flo o d e d p a s tu r e la n d b o rd e rin g th e la k e by
March 26, 19f?2.
These flo o d e d a re a s were u s e d b y ducks and g e e se .
la k e became i c e f r e e A p r il l i t .
The
P o r tio n s o f bays and a re a s around p o in ts
were open A p r il 6 .
W aterfow l o b serv ed in c lu d e d : Canada g eese (B ra n ta c a n a d e n s is ) ,
l e s s e r snow geese (Chen h y p e rb o re a h y p e rb o re a ) , w h is tlin g swans ( O lor
colum bianus) , m a lla rd s (Anas p la ty rh y n c h o s ) , g ad w alls ( Anas s t r e p e r a ) ,
p i n t a i l s ( Anas a c u ta t z i t z i h o a ) , g reen-w inged t e a l s ( Anas c a r o l i n e n s i s ) ,
b lu e -w in g e d t e a l s (Anas d i s c o r s ) , cinnamon t e a l s ■(Anas c y a n o p te ra s e p te n tr io n a liu m ) , b a ld p a te s (Mareca am erican a) , s h o v e lle r s ( S p a tu la c ly p e a ta ) ,
re d h e ad s (A ytha a m erica n a ) , can v as-b ack s ( Aythya v a l i s i n e r i a ) , l e s s e r
scaups (Aythya a f f i n i s ) , b u f f Ie h e ads ( E ncephala a lb e o la ) , American
g o ld e n -e y es (B ueephala c la n g u la am erican a) , ru d d y ducks ( Qxyora jamaic e n s is r u b id a ) , and r e d b r e a s te d m ergansers (Mergus s e r r a t o r serra to r) .
One w hite-w inged s c o t e r (M e la n itta d e g la n d i) was s e e n .
The e a r l i e s t o b s e r v a tio n was made March 26, 1952.
A r e s i d e n t farm er
s t a t e d t h i s was th e f i r s t day he had n o tic e d ducks on th e a r e a .
p i n t a i l s , c a n v a s-b a c k s, and American g o ld e n -e y es were i d e n t i f i e d .
M a lla rd s ,
The
fo llo w in g day b a ld p a te s , re d h e a d s , l e s s e r s c a u p s , b u f f le h e a d s , l e s s e r
snow g e e s e , Canada geese,; and w h is tlin g sw ans, p lu s th e s p e c ie s above.
-1 3 were see n w ith ah e s tim a te d 8,000 b ir d s p r e s e n t.
tio n s o c c u rre d a t n ig h t (L in c o ln , 19f>0).
E v id e n tly la r g e m igra­
Numbers in c r e a s e d n o tic e a b ly
from e a r l y evening t o th e fo llo w in g m orning.
The g r e a t e s t number ob­
se rv e d was an e s tim a te d 18,200 on March 29.
L ate m ig ra n ts co u ld n o t be d is tin g u is h e d from e a r l y r e s i d e n t s .
T erm in atio n d a te s o f m ig r a tio n were su g g e ste d b y p o p u la tio n num bers5
numbers o f lo n e p a i r s a s compared t o l a r g e r g ro u p s3 ..and/or b e g in n in g o f
n e s tin g .
The s p rin g m ig ra tio n ex ten d ed o v er a Biinumum o f 98 d a y s,
•March 26- J u ly I .
A r r i v a l, peak m ig r a tio n , and te rm in a l m ig ra tio n d a te s
as th e d a ta s u g g e s t a re g iv e n by s p e c ie s i n Table I .
G ira rd (1939* 19Ul) g iv e s q u ite s im ila r d a te s f o r t h e , main f l i g h t
o f m a lla rd s and s h o v e lle r s i n w e ste rn M ontana.
The maximum number o f l e s s e r snow geese o b se rv e d , 1 2 ,0 0 0 , A p ril 6 ,
was o n ly l / 3 to 1 /10 th e number e s tim a te d by 2 r e s id e n ts f o r th e p re v io u s
day.
Usage by la r g e numbers i s s u b s ta n tia te d by a r e p o r t o f 1^0,000 f o r
A p ril 1 8 -1 9 , 19^0 (U. S . F is h and W ild lif e S e r v ic e , M isso u ri R iv e r B asin
S t u d i e s , c o r r e spondence) .
M a lla rd s , p i n t a i l s , redheads and g ad w alls d is p la y e d somewhat s im ila r
sex r a t i o s th ro u g h o u t t h e i r m ig ra tio n s (T a b le - I r ) s u g g e s tin g no d i f f e r ­
e n t i a l m ig ra tio n o f th e s e x e s .
Hochbaum (19U6) found th e fo llo w in g sex
r a t i o s d u rin g th e l a s t two weeks o f A p r il and th e f i r s t week o f May i n
M anitoba, Canada: m a lla r d s , 102:1003 p i n t a i l s , 109:100; re d h e a d s , 1 38:100.
The sex r a t i o o f red h ead s d u rin g s p rin g m ig r a tio n i n Iowa was lb.2sl00
(Low, 19U5)*
-iU ~
Table I .
-
A r r iv a l, p e ak , and term in al- m ig ra tio n d a te s f o r w aterfo w l
o b serv ed a t G re e n fie ld s L ake, 1952.
S p e c ies
M a lla rd
P in ta il
A. G olden-eye
C anvas-back
B ald p ate
Redhead
B u ffle h e a d
L e s s e r Scaup
S h o v e lle r
G. ¥ . . T eal
Gadwall
Cinnamon T eal
Ruddy duck
B. 'W. T eal
L. Snow Goose
Canada Goose
1W h istlin g Swan
■ A rriv ed
By
3 /2 6
3 /2 6
3 /2 6
3 /2 6
3 /2 7
3 /2 7
3 /2 7
3 /2 7
h/ 6
k/6
h/6
L /6
U/20
1 /2 8
3 /2 7
3 /2 7
3 /2 7
Peak
T erm inated
About
3 /2 6 - 1 / 2
3/28-rh/h
IiA-IO
U /9-15
aA o1
a / 201
5/20%
5A 1
■ 5 /5 1 .
/ -a/a
3 28
a / 1 6 -2 2
1 /2 2 -2 8
a/25-5/1
a /12- i s
5 /3 -9
5 /a - io
5 /9 -1 5
5 /3 - 9
5 /ia -2 0
a /1 -7
-
5 /5 1
5A 1
5 / ig 1
5 /2 0 1
5/20^
7 /1 3
5/253
.
I - M a jo rity ' o f b ir d s o b serv ed as lo n e p a i r s j
^ - B eginning o f n e s tin g ;
5 - P o p u la tio n num bers.
I
Table U .
Sex ra tio s ^ - o f w aterfo w l i d e n t i f i e d d u rin g s p rin g m ig ra tio n a t G re e n fie ld s Lake, 1952.
S p e c ie s
M allard
P in ta il
Redhead
March
26-30
128:100
(1*05:317)
105:100
(1501:11*23)
133:100
(1*:3)
Gadwall
C anvas-back
L e s se r S c.
1250:100
(50 sU)
933:100
(2 8 :3 )
A p ril
A p ril
6 -7
13-11*
129:100 122:100
( 27: 21) (6 7 :5 5 )
IOl*:100 127:100
( 71: 68) (1 2 8 : 101)"
ll*2*:lQQ
(1 3 :9 )
133:100
(1 2 :9 )
322:100
(8 7 :2 7 )
267:100
(8 :3 )
A p ril
20r-21
137:100
(1*1 :3 0)
105:100
(2 0 :1 9 )
338:100
( 88: 26)
167:100
(5 5:33)
(2: 0)
100:100
( 7: 7)
107:100
(29:27)
200:100
(6: 3)
216:100
(51*.:25)
200:100
(l*:2)
11*3:100
(5 7 : 1*0 )
19l*:100
(6 0 :3 1 )
516:100
(1 2 9 :2 5 )
(1 : 0 )
156:100
( 28: 18)
110:100
(11: 10)
1*70:100
(1*7:10)
Cinnamon T.
(1 : 0 )
B. ¥ . T eal
B ald p ate
G. ¥ . T e a l
S h o v e lle r
116:100
(1*1*1:379)
100:100
(1*:1*)
100:100
■ (3 :3 )
^ H ales sfem ales
111*: 100 133:100
(3 2 : 28) (9 2 :6 9 )
100:100 129:100
( 2 : 2)
(2 2 :1 7 )
163:100 200:100
(LI*:27) (122: 61)
A p ril
27-28
May
l*-5
May
11-12
May
18-20
138:100
( 22: 1 6)
109:160 115:100
(50:1*6) ( 23: 20)
200:100 1300:100
( 8 : 1*)
( 26: 2 )
208:100
(5 2:25)
225:100 213:100
(1 7 :8 )
( 9 : 1*5
133:100 190:100 290:100
(20:15) (1 9 :1 0 ) "(1*2:15)
150:100
( 2l* :l6 ) "
11*0:100 150:100
(3 5 :2 5 ) (1 2 : 8)
1*53:100
(6 8 :l5 )
Average '
127:100
(1*99:393)
107:00
(1700:1592)
131*: 100
(8 7 :6 5 )
111:100
(131:121)
1*02:100
( 265: 66)
221:100
(197:89)
236:100
(33:11*)
205:100
( 82: 1*0 )
123:100
(671:550)"
11*7:100
(11*6:99)
293:100
(^13:111)
-1 6 A d i f f e r e n t i a l m ig r a tio n , w ith an e a r l y movement o f m a le s , i s
s u g g e ste d f o r th e c an v a s-b ac k s and l e s s e r s c a u p s .
The same tr e n d i s
p o s s ib ly su g g e s te d f o r b lu e-w in g ed and cinnamon t e a l s .
Sm ith (19I16) .
found th e c an v as-b ack s sex r a t i o to be. 230;100 in e a r l y m ig ra n ts and
120:100 a t th e peak o f m ig ra tio n i n M in n eso ta.
The c an v as-b ack s sex
r a t i o was 189:100 and l e s s e r s c a u p s, 201:100 d u rin g th e s p rin g m ig ra tio n
i n M anitoba, Canada (Hochbaum, 19I4.6 ) .
The sex r a t i o o f l e s s e r scaups was
156:100 and 186:100 d u rin g March and A p ril r e s p e c tiv e ly i n so u th w e ste rn
'.Washington (B e er, 191:5).
B e n n e tt (1938) r e p o r te d a b o u t 150:100' d u rin g
m ig ra tio n o f b lu e-w in g ed t e a l s in Iow a.
In M in n eso ta, b lu e-w in g ed t e a l s
showed a marked te n d e n c y f o r m ales t o p re c ed e fem ales (E ric k so n , 19k3).
The r a t i o o f b a ld p a te m ales to fem ales in c re a s e d a s m ig ra tio n p ro ­
g re s s e d .
S p rin g sex r a t i o i n M innesota was 121:100 (E ric k s o n , 19U3).
B eer (19I4.5.) r e c o r d e d . 111).: 100 and 115:100 d u rin g March and A p ril r e ­
s p e c tiv e ly .
E a r ly m ig ra n ts o f green-w inged t e a l s showed e q u a l numbers o f m ales
and fe m a le s .
L a te r th e r a t i o o f m ales in c r e a s e d .
Beer (19U5) r e p o rte d
103:100 f o r March and 100:100 f o r A p r il.
. S h o v e lle rs e x h ib ite d a b a la n c e d sex r a t i o i n e a r l y m ig r a n ts , w ith
r a t i o s becoming u n b a lan c e d i n fa v o r o f m ales a s m ig ra tio n p ro g re s s e d .
E ric k s o n (19^3) found a sex r a t i o o f 115:100 i n e a r l y s p rin g and 165:100
i n l a t e s p r in g .
BREEDING POPULATION
A b re e d in g p o p u la tio n o f a t l e a s t 3lt-1 p a i r s (T able I I I ) on th e la k e
-1 7 -
T able I I I .
S p e c ies
B reeding p o p u la tio n as in d ic a te d by t e r r i t o r i a l p a i r s
arid p a ir s /m ile o f s h o r e lin e type a t G re e n fie ld s Lake,
195>2.
T o ta l
P a ir s
Greasewood^
P a ir s /m ile
G rass^
P a irs /m ile
2 .3
2 .3
3*3
2 .3
1 .3
»3
1 .8
l.l*
1 .3
.7
.3
.9
2 1 .9
3 .1
1 .6
2 .1
1 . 1*
1 .0
.2
1 .2
»3
.6
.3
P in ta il
. 83
M allard
39
G adwall
&
h2
B. ¥ . T eal
G. 'W. T e a l
23
6
Cinnamon T eal
S h o v e lle r
31
20
B a ld p a te '
21
L e s se r Scaup
Redhead
9
C anvas-back
h
8
Ruddy duck
T o ta l
31*1 •
*
6
7
8 e£U Tniles s h o r e lin e ;
1 1 . U6 m ile s s h o r e lin e ;
1 .8 8 m ile s s h o r e l i n e .
-
■
1 2 .0
A g r ic u ltu r a l Land?
Pa ir s /m ile
1 .1
.3
’ 1 .6
2.7
.2
i.i
i.l
.3
9.0
-1 8 I n 19!?2 was in d ic a te d by c o u n tin g t e r r i t o r i a l p a ir s and lo n e m ales
(Hochbaum, 1 9 h b )•
S p e c ie s com p o sitio n was as fo llo w s : p i n t a i l s , 2h p e r
/
c e n t; g a d w a lls , 1 6 ; b lu e-w in g ed t e a l s , 1 2; m a lla rd s , 11; s h o v e ll e r s , 9 ;
green-w inged t e a l s , 7J b a ld p a te s , 6 ; l e s s e r sc a u p s, 6 ; re d h e a d s , 3 ;
ru d d y d u ck s, 2; cinnamon t e a l s , 2; c a n v a s-b a c k s, I .
These f ig u r e s do
n o t in c lu d e th e e x te n s iv e c a t t a i l m arsh and th e r e f o r e do n o t r e f l e c t th e
tr u e p r o p o r tio n o f w a te r n e s tin g s p e c ie s f o r th e e n t i r e a r e a .
N e stin g
s tu d ie s in d ic a te th e re d h e a d , f o r exam ple, i s one o f th e more common
n e s te rs .
The greasew ood s h o r e lin e , 3 9 .0 p e r c e n t o f th e t o t a l s h o r e lin e ,
su p p o rte d 35 p e r c e n t o f th e t e r r i t o r i e s ; g r a s s , 5 2 . U, lj.0 ; a g r i c u l t u r a l
la n d , 8 . 6 , 5*
I r r e g u l a r i t y o f s h o r e lin e , p re se n c e o f s m a ll i s l a n d s , and
b ushes r e s t r i c t i n g v i s i o n were f a c t o r s which may have been r e s p o n s ib le
f o r th e g r e a t e r d e n s ity o f t e r r i t o r i a l p a i r s alo n g th e greasew ood s h o re ­
l i n e (T able I I I ) .
See Hochbaum (l9W l) f o r a d is c u s s io n o f e n v iro n m e n ta l
in f lu e n c e s on s iz e o f t e r r i t o r y .
O ther s p e c ie s n e s tin g on th e a re a in c lu d e d : common t e r n (S te rn a
h iru n d o h iru n d o ) , F r a n k li n ’s g u ll (L aru s p ip ix c a n ) , r i n g - b i l l e d g u ll
(L . d e la w a re n s is ) , C a l if o r n ia g u l l (L1 c a l i f o r n ic u s ) , ' MLlson1s p h a laro p e
(Steganopus t r i c o l o r ) , m arbled godw it (-Limosa fe d o a ) , w i l l e t (C atoptro p h o ru s sem ipalm atus in o r n a tu s ) , a v o c e t (R e c u r v ir o s tr a am erican a) ,
s o r a ( F orzana C a r o lin a ) , e a r e d grebe (Colymbus n i g r i c o l l i s c a l i f o r n i c u s ) ,
y ello w -h ead ed b la c k b ir d (X anthocephalus x a n th o c e p h a lu s ) , red -w in g ed
b la c k b ir d (A g e laiu s p h o e n ic e u s ), lo n g - b i l l e d m arsh wren ( T elm atodytes
■
-1 9 p a l u s t r i s ) , c o o t (F u lic a a m erica n a ) <» rin g -n e c k e d p h e a sa n t ( F h asian u s
• c o lc h ic u s to r q u a tu s ) , crow (Corvus b ra c h y rh y n ch o s) , s h o r t- e a r e d owl
(A sio flanm eus flan m eu s) 9 m arsh hawk (C irc u s h u d so n iu s) .
NESTING STUDY
Methods
Complete n e s t s e a rc h e s o f a l l c o v er was n o t f e a s i b l e »
Tw enty-seven
r e c ta n g u la r p l o t s , l £0 b y 300 y a rd s , each in c lu d in g 15>0 y a rd s o f s h o re ­
l i n e , were s e le c te d a s b e in g r e p r e s e n ta tiv e f o r s e a rc h e s o f g ra s s and
greasew ood c o v e r ty p e s .
The 300 y a rd d e p th was c o n sid e re d s u f f i c i e n t as
s i m i l a r s tu d ie s in d ic a te d t h a t th e m a jo r ity o f n e s ts a re fo u n d w ith in
t h i s d is ta n c e from w a te r (B e n n e tt, 1938; G ira rd , 1 9 U l)«
A d d itio n a l a re a s
were se a rc h e d as tim e p e r m itte d . I t was n o t c o n sid e re d d e s ir a b le to
I
s e a rc h a g r i c u l t u r a l ty p e s . In te rv ie w in g la n d owners engaged i n a g r i­
c u l t u r a l a c t i v i t i e s p ro v id e d some in fo r m a tio n .
(F ig . 2 ) was c o v ered .
The e n t i r e c a t t a i l marsh
The d a te s o f , and e f f o r t s expended i n o rg a n iz ed
n e s t s e a rc h e s are g iv e n i n Table IV .
S upplem entary s e a rc h e s were made
by th e a u th o r d u rin g r e v i s i t s .
S ix ty f o o t r o p e s , w ith t i n cans a tta c h e d a t 10 f o o t i n t e r v a l s , were
dragged betw een two men i n a re a s where c o v er p e rm itte d to f l u s h n e s tin g
fe m a les (Sow ls, 1 9 5 0 ).
Greasewood and em ergent v e g e ta tio n were walked in '
a w eaving manner w ith a p p ro x im a te ly 20 to 30 f o o t i n t e r v a l s betw een men.
A t o t a l o f 222 a c tiv e and 112 in a c tiv e n e s ts were found d u rin g 1951
and 1952 as in d ic a te d by s p e c ie s in Table V.
• a c tiv e i f th e fem ale was s t i l l a tte n d in g .
N ests were c l a s s i f i e d as
Those te rm in a te d b y h a tc h in g .
-2 0 Table 17.
D ates and man h o u rs o f o rg a n iz e d n e s t s e a rc h e s a t
G re e n fie ld s L ake, 1951 and 1952.
Date
5 /2 6 , 5 /27
1951
Number
Men
11
Man
Hours
175
6/ 13, 6/ l l i ,
6 / l 5 , 6/ l 6
6
138
7
133
7/ 6 , 7 /7
T o ta l Man Hours
Table V.
Date
5 /3 0 , 5 /3 1 ,
■ 6/ l
6/ 3 0 , 7 /1
1952
Number
Men
11
Man
Hours
.2h2
9
106
31#
UU6
Number o f a c tiv e and in a c t iv e duck n e s ts found a t
G re e n fie ld s L ake, 1951 and 1952.
S p e c ies
P in ta il
M allard
Gadwall
B. W. T eal
G. ¥ . T eal
U nid. T eal
S h o v e lle r
B ald p ate
L e s s e r Scaup
Redhead
C anvas-back
Ruddy duck
T o ta l
. ■
Number o f a c tiv e
n e s ts found
1951 1952 T o ta l
19
35
51
16
16
32
12
22
3h
20
8
12
6
9
15
3
2
9
17
I
U
10?
5
3
10
8
3
2
n5
8
5
19
25
h
6
222
Number o f in a c tiv e ■
n e s ts found
' 1951. 1952 T o ta l
Uo
27
13
UL
15
h
6
13
19
6
6
12
2
7
5
8
h
U
2
2
2
kh
5
2
7
68
112
2
-2 1 d e st r a c t i o n , o r d e s e r tio n when found were c la s s e d as i n a c t i v e .
These
w ere i d e n t i f i e d to s p e c ie s by com paring th e e g g s , f e a t h e r s , and down w ith
r e fe re n c e c o l l e c t i o n s .
Subsequent d is c u s s io n s r e f e r t o a c tiv e n e s t s o n ly
u n le s s s p e c if ie d o th e rw is e .
West lo c a tio n s were marked by p la c in g a 2 f o o t l a t h I ^ s te p s o r a
w illow s ta k e Ifp f e e t from la n d and w a ter n e s ts r e s p e c t i v e l y .
W ater n e s ts
in c lu d e th o s e on sm a ll is la n d s as w e ll as th o se i n em ergent v e g e ta tio n .
West num ber, d a te , s p e c ie s , number o f eggs and o th e r p e r t i n e n t d a ta were
re c o rd e d on th e m arker and i n a f i e l d n o te b o o k .
L o c a tio n was p l o t t e d on
a map.- P re c a u tio n s were ta k e n to av o id tra m p lin g v e g e ta tio n ab o u t n e s ts
to le s s e n danger o f p r e d a tio n (B e n n e tt, 1938; Kalmbach, 1 9 3 8 ).
Wests
were r e v i s i t e d a t a p p ro x im a te ly w eekly i n t e r v a l s u n t i l te r m in a tio n .
P e r ti n e n t d a ta p r e ta in in g to th e h i s t o r y o f th e n e s t were re c o rd e d .
The
cause o f te rm in a te d n e s ts was d eterm in ed a f t e r c a r e f u l ex am in atio n o f
n e s t and e g g s.
The heavy i n t a c t egg membranes (F ig . ?)• w ere th e m ost conspicuous
f e a tu r e s o f a s u c c e s s f u l n e s t .
T his membrane i s e v id e n tly p l i a b l e enough
a t h a tc h in g to r e s i s t c ru s h in g .
212 membranes were fo u n d .
From a sample o f 223 s u c c e s s f u l eg g s,
The a c t i v i t i e s o f fem ale and young e v id e n tly
c ru s h th e h a tc h e d egg s h e l l s i n t o fra g m e n ts .
From 108 s u c c e s s f u l n e s t s ,
o n ly 2 i n t a c t h a tc h e d egg s h e l l s were fo u n d , b o th ru d d y d u ck .
Egg caps
from s u c c e s s f u l eggs were p r e s e n t, b u t o th e rs u n d o u b te d ly s u f f e r e d th e
same f a t e as th e egg s h e l l s .
Somewhat s im ila r d e s c r ip tio n s o f s u c c e s s fu l
n e s ts have been giv en b y W illiam s and M a rsh a ll (1 9 3 8 ), B e n n e tt (1938),
-2 2 -
F ig . 7 .
F ig . 8 .
Membranes from h a tc h e d eggs c h a r a c t e r i s t i c
of a su c c e ssfu l n e s t.
P i n t a i l eggs d e stro y e d by skunk showing
c h a r a c t e r i s t i c c ru s h in g .
-2 3 G ira rd (1939) , Low (19k!?) 3 and Sowls (19I48) . .
to v a rio u s so u rc e s (se e b e lo w ).
D e s tr n o tio n w a s a t t r i b u t e d
A n e s t was c o n sid e re d d e s e r te d when i t
became e v id e n t t h a t th e fem ale was no lo n g e r i n a tte n d a n c e .
N e stin g Cover
The 222 n e s ts found were lo c a te d as fo llo w s : greasew ood, l l 3 ;
i s l a n d s , hS, em ergent v e g e ta tio n , 38; g r a s s , 26.
L o c a tio n by s p e c ie s i s
g iv e n i n Table V I.
E ig h ty - th r e e p e r c e n t o f th e n e s ts i n greasew ood were a t th e b a se
o f b u s h e s , 17 p e r c e n t in g ra s s betw een b u s h e s .
The dom inant p l a n t a t
63 p e r c e n t was f o x t a i l b a r le y o r b lu e ste m . ' About 93 p e r c e n t o f is la n d
n e s ts were i n greasew ood (F ig . 3 ) , th e o th e r s i n g r a s s .
n e s t was found on any i s l a n d .
No more th a n one
N in e ty -sev e n p e r c e n t o f n e s ts i n em ergent
v e g e ta tio n were i n c a t t a i l , 3 p e r c e n t i n a l k a l i b u lr u s h .
F a l l and e a r l y s p r in g plow ing e lim in a te d a p p ro x im a te ly 80 p e r c e n t
o f th e a g r i c u l t u r a l ty p e as n e s tin g c o v e r.
a v a ila b le .
f o r n e s ti n g .
The rem ain d er i n a l f a l f a was
In te rv ie w in g landow ners in d ic a te d a l f a l f a was l i t t l e u t i l i z e d
Only two n e s ts were r e p o r te d d u rin g h aying o p e r a tio n s , and
b o th were d e s tro y e d by mowing.
E a r ly i r r i g a t i o n fo llo w e d by mowing su g ­
g e s te d a l f a l f a would be hazardous n e s tin g c o v e r.
The average d is ta n c e s from n e s t to w a te r i n g ra s s and greasewood
r e s p e c t i v e l y w e re: p i n t a i l s , 109 y a r d s , 6l y a rd s ; m a lla r d s , 90, 33; gadw a l l s , 90, 3U; s h o v e ll e r s , 3 9 , 28; l e s s e r sc a u p s, ------, 27; b a ld p a te s , ----- ,
33; green-w inged t e a l s , 1 7 , 39; b lu e-w in g ed t e a l s , 3 6 , 28; re d h e a d s ,
10.
B en n ett (1938) found b lu e-w in g ed t e a l n e s ts to average L i . 3 y a rd s
.
-
Table VX.
21-
Cover type o f a c tiv e n e s ts found a t G re e n fie ld s Lake,
1951 and 1952.
S p e c ie s
P in ta il
M allard
G adwall
B. "W. T eal
G. W. T eal
S h o v e lle r
B ald p ate
L e s se r Scaup
Redhead
C anvas-back
Ruddy duck
T o ta l
•T otal
W ests
5U
32
3k
20
15
. 8
5
19
25
It
6
222
P e rc e n tag e o f n e s ts i n
Greasewood
I s la n d s
Em ergents
57 .U
37.5
85.3
65.0
86.7
37.5
100.0
36.8
8.0
51.8
25.9
25.0
2 .9
R '
3li.lt*
16.7
3 .1
11 .8
35.0
13.3
37.5
25.0
63.2
U.o
100.0
16.7
19 .It
G rass
88.0
83.2
17.1
- M uskrat h ouses and m a tte d em ergent v e g e ta tio n .
11.7
■
from w a ter i n Iow a.
-
25> -
G ira rd (19I4I ) r e p o r te d m a lla rd n e s ts av erag ed 1 18.7
y a rd s from w a te r and green-w inged t e a l s 3h»2 y a rd s i n w e ste rn Montana,
w ith b lu e-w in g ed t e a l s , cinnamon t e a l s , s h o v e lle r s and b a ld p a te s w ith in
th e s e e x tre m e s .
R e sts i n em ergent v e g e ta tio n were n e v e r f a r from open w a te r p ro v id e d
by " n a t u r a l openings" o r m uskrat a c t i v i t y .
y a rd s .
Redhead n e s ts averaged 11
S ix ty - f o u r p e r c e n t were n e a r " n a t u r a l o p e n in g s".
Low (l9ll5>)
found re d h e a d n e s ts av erag ed 28 y a rd s from m uskrat lo d g e s which were th e
n e a r e s t open w a te r f o r Sh p e r c e n t o f th e n e s t s .
D aring 19!?1, a p p ro x im a te ly l / 3 o f th e c a t t a i l m arsh had been w in te r
g ra z e d b y c a t t l e , Ul p e r c e n t o f th e re d h e ad n e s ts were found i n t h i s
p o r ti o n .
F a te o f eggs and n e s ts
R e s t c o n s tr u c tio n , e g g s, and c lu tc h s iz e were s im ila r to th o se de­
s c r ib e d by v a rio u s a u th o r s .
The h a tc h in g s u c c e ss o f £03 eggs from la n d and U69 eggs from w ater
n e s ts was 25.8 and U5.8 p er. c e n t r e s p e c t i v e l y i n 1951 ( Table V I l) ,
W illiam s and M a r s h a ll. (1938) re c o rd e d an egg su c c e ss i n U tah a s fo llo w s :
g a d w a lls, 85 p e r c e n t; cinnamon t e a l s , 8U; re d h e a d s , 26; m a lla rd s , 60 ;
p i n t a i l s , 82; ruddy d u c k s, 52; s h o v e ll e r , 80.
G ira rd (l9 U l), i n w e ste rn
M ontana, found an egg su c c e ss ran g e o f 69.7 p e r c e n t f o r s h o v e lle r s to '
75.2 p e r c e n t f o r green-w inged t e a l s , w ith m a lla rd s , b a ld p a te s , cinnamon
t e a l s and b lu e-w in g ed t e a l s w ith in th e s e e x tre m e s.
an egg su c c e ss o f U5 p e r c e n t f o r re d h e ad s i n Iowa.
Low (l9U5) r e p o r te d
-2 6 -
Table ' VIZ.
Egg s u c c e ss o f la n d and w a te r n e s ts a t G re e n fie ld s Lake,
1951 .
_______ P e r c e n t U n su c c essfu l from _________________
S p e c ie s
Mo. P e rc e n t
■Unknown
L ate
_____________Eggs H atched Skunk P re d a to r Undeveloped Embryo M isc. D e se rtio n
EGGS OF
LMD NESTS
P in ta il
M allard
G adwall
S h o v e lle r
B ald p ate
B. ¥ . T eal
G. W. T eal
L e s s e r S c.
T o ta l
EGGS OF
WATER NESTS
P in ta il
M allard
L e s se r S c .
Redhead
Ruddy Duck
C anvas-back
T o ta l
100
23
200
18
17
75
h9
21
503
58.0
78.3
1 8 .0
55.6
0.0
1 0 .7
0.0
0.0
25.8
30.0
17 .U
73.5
38.9
100.0
76.0
79.6
57.1
6 2 .2
U.o
1.0
6.5
1.5
12.0
7.0
U.3
.5
5.5
1.3
20.U
1:2.9
3.6
1.6
.2
U.o
2.6
—
35
120
66
205
33
10
1:69
U5.7
5o.o
83.3
35.1
36.1:
0.0
1:5.8
17.1
12.1
3.0
5.7
.8
1.5
10.2
6.1
6.7
1.5
20.5
5.8
11.5
9 .1
2.9
i5 .o
' 1.5
13.6
3.0
28.6
27.5
20.5
U5.5
100.0
i o . U 23.5
-
27-
P re d a tio n ' caused th e f a i l u r e o f 69«8 p e r c e n t o f eggs from la n d and
3 .0 p e r c e n t o f eggs- from w a te r n e s t s .
The m a jo r ity o f eggs from w ater
n e s ts l i s t e d as h av in g a m is c e lla n e o u s f a t e i n T able V II were re c o rd e d
fo llo w in g a sudden r i s e o f w a te r l e v e l i n th e c a t t a i l marsh®
This
n e c e s s ia te d r a p id a d d itio n o f new n e s t m a te r ia ls by th e fe m a les to p re v e n t
n e s ts from b e in g in u n d a te d .
I t i s p o s s ib le t h a t th e eggs were e i t h e r
pushed in to th e w a ter o r b u rie d i n th e n e s t d u rin g t h i s c o n s tr u c tio n .
L a te embryos r e f e r to u n h a tc h e d eggs w hich c o n ta in e d embryos i n v a rio u s
s ta g e s o f developm ent.
The f r e q u e n t o ccu rren ce o f l a t e embryos and .un­
developed eggs i n re d h e ad c lu tc h e s p o s s ib ly was a r e s u l t o f s tra n g e
fem ales d e p o s itin g eggs i n th e n e s ts a f t e r in c u b a tio n b e g a n .
h as been d e s c rib e d f o r red h ead s b y Low (l 9 k %).
This h a b i t
L ate embryos and un­
developed eggs o f o th e r s p e c ie s g e n e r a lly were r e s t r i c t e d to a s in g le
egg from s u c c e s s f u l c lu tc h e s .
S ix ty -o n e la n d and l|6 w a te r n e s ts h ad a h a tc h in g su c c e ss o f 26.2
and 69*7 p e r c e n t r e s p e c t i v e l y i n 195)1 ( Table V I I I ) .
Kalmbach (1939) i n
a re v ie w o f more th a n 7,600 w a terfo w l n e s ts i n 22 s tu d ie s found an a v e rage su c c e ss o f 60 p e r c e n t.
A n e s t s u c c e ss o f 5U.8 p e r c e n t f o r 250 b lu e -
w inged t e a l n e s ts i n Iowa was re c o rd e d b y B en n e tt (1 9 3 8 ).
Low (19US>)
found a n e s tin g su c c e ss o f 56.2 p e r c e n t f o r 160 re d h e ad n e s ts in Iowa.
Sowls (l9 l;8 ),
i n M anitoba, Canada, r e p o r te d th e fo llo w in g n e s t s u c c e s s :
M a lla rd s , 36 n e s t s , 33 p e r c e n t; g a d w a lls , 6 , 16; p i n t a i l s , 3h, 23; b lu e winged t e a l s , 3 3 ,3 5 ; s h o v e ll e r s , 8 , 25; re d h e a d s , 5 2 , li2; c a n v a s-b a c k s,
- 2I4, 58; l e s s e r s c a u p s , 10, 20; ru d d y d u ck s, 3 , 33.
E a r l (1950) found 60
-2 8 -
Table V I I I .
S p e c ie s
LAUD NESTS
P in ta il
M allard
G adwall
S h o v e lle r
B ald p ate
B. ¥ . T eal
G. ¥ . T eal
L e s se r Scaup
T o ta l
¥ATER NESTS
P in ta il
M allard
Redhead
L e s se r Scaup
Ruddy Duck
C anvas-back
T o ta l
S uccess o f la n d and w a te r n e s t s a t G re e n fie ld s L ake, 1951 •
No.
N ests
P e rc e n t
H atched
. 57.1
5o.o
Ht
h
22
3
2
8
1 8 .2
'
333
Skunk
P er c e n t d e stro y e d by
Unknown
M isc.
D e se rtio n
P re d a to r
' '
7.1
35.7
25.0
72.7
33.3
0 .0
100.0
12.5
25.0
lu5
75.Q
83.3
12.5
2
61,
0 .0
0 .0
26.2
5 0 .0
50.0
60.7
3.3
5
60.0
. 20.0
12
66.7
76.5
85.7
5o.o
6
17 .
7
h
I
U6
16.7
3.2
6.6
8.3
5.9
25.0
20.0
1^.3
1 7 .6
5o.o
100.0
0 .0
69.7
a .5
33.3
U»3
h .3
21.7
-
29-
m a lla rd n e s ts to have a 92 p e r c e n t h a tc h in g su c c e ss i n C a l if o r n ia .
Human i n te r f e r e n c e i s th o u g h t t o have cau sed th e d e s e r tio n o f 3
n e s t s c o n ta in in g I egg each and 5 w ith com plete c lu tc h e s .
S ix te e n i n ­
a c tiv e d e s e r te d n e s ts o r n e s t forms o f 9 s p e c ie s w ith I to 9 eggs each
were found, s u g g e s tin g t h a t fem ales n o t uncommonly abandon uncom pleted
n e s ts w ith o u t human i n t e r f e r e n c e .
S ix n e s ts were d e s e r te d f o r unknown
re a so n s. .
S u rp lu s i r r i g a t i o n w a te r e n te rin g , th e c a t t a i l m arsh flo o d e d two
n e s ts .
C a lif o r n ia g u l l s were s u sp e c te d o f d e s tro y in g one n e s t .
O ther
a v ia n p r e d a to r s p r e s e n t which may have been re s p o n s ib le were crow s/and
rin g -b ille d g u lls .
Two n e s ts were d e s tro y e d by unknown p r e d a to r s , and
one in c u b a tin g fem ale was k i l l e d by an unknown mammalian p r e d a to r , p o s s i ­
b ly a mink (M u stela v is o n ) o r w e a se l (M. f r e n a t a ) .
S tr ip e d skunks
(M ep h itis m e p h itis ) were re s p o n s ib le f o r th e g r e a t e s t n e s t d e s tr u c tio n ,
6 0 .7 p e r c e n t o f la n d and It.3 p e r c e n t o f w a te r n e s t s .
C h a r a c te r is tic s
o f skunk d e s tr u c ti o n w ere: n e s t u s u a ll y to r n a p a r t | egg s h e l l s l e f t in
im m ediate v i c i n i t y o f n e s t ; some egg c o n te n ts rem ain in g i n n e s t and on
'
egg s h e l l s ; and l / l t to e n t i r e egg c h a r a c t e r i s t i c a l l y c ru sh ed (F ig . 8 ) .
These c h a r a c t e r i s t i c s a g re e w ith th o s e r e p o r te d b y Sowls (19U8) and ■
R earden (1 9 9 1 ).
'
.
"
Human i n t r u s i o n i s n o t b e lie v e d to have in c re a s e d n e s t v u l n e r a b i l i t y
to sk unks.
T h i r ty - s ix in a c t iv e la n d n e s t s found in 1991 h ad a h a tc h in g
su c c e ss o f 1 6 .7 p e r c e n t and k9 f o r 1992 had a su cc e ss, o f 20. 1: p e r c e n t.
S uccess was below t h a t o f a c tiv e n e s ts b o th y e a r s .
Kalmbach (1938) found
-30'
s im ila r r e s u l t s and concluded t h a t i n t r u s i o n by c a r e f u l o b s e rv e rs d o e s '
n o t a f f o r d skunks a m arked a d v an ta g e .
W ater was an e f f e c t i v e skunk b a r r i e r as in d ic a te d b y th e m inor p r e ­
d a tio n , h»3 p e r c e n t, on w a te r n e s t s .
o b serv ed w alking i n sh a llo w w a te r .
Only one o f many skunks seen was
C u y le r' (192U) s t a t e s "skunks a re
c h i e f l y t e r r e s t r i a l , a lth o u g h th e y h u n t alo n g th e edges o f stream s f o r
fro g s and c r a y f is h , and l i k e racco o n s even s lo s h minnows o u t o f w ater
w ith t h e i r paw s".
The two w a te r n e s ts d e stro y e d b y skunks were on sm a ll •
i s la n d s a few f e e t from th e m ain lan d , w ith ' w a ter d ep th l e s s th a n an in c h
i n th e in te r v e n in g sp a c e .
Land n e s ts on th e la r g e p e n in s u la i n th e s o u th - c e n tr a l p a r t o f th e
la k e (F ig . l ) s u f f e r e d th e g r e a t e s t skunk p r e d a tio n , 77=3 p e r c e n t; o th e r
la n d n e s ts ab o u t t h e ' la k e £ 1 .3 p e r c e n t.
The u n u su al s e v e r i t y o f skunk
p r e d a tio n gave im petus t o co n d u ct an e x p erim en t on th e e f f e c t o f skunk
r e d u c tio n upon su c c e ss o f la n d n e s t s .
From A p r il 6 to A ugust 2 , 19£2, a s t r i n g o f number I s t e e l tr a p s
b a i t e d w ith c h ick e n eggs and m eats were s e t a c ro s s th e p e n in s u la a t
a p p ro x im a te ly 100 f o o t i n t e r v a l s to c a tc h skunks moving i n t o th e a r e a .
No skunk dens were found on th e p e n in s u la i n 1 9 £ l o r 19£2, p o s s ib ly due
t o th e h ig h w a te r t a b l e .
No skunks were removed from o th e r n e s tin g a re a s
a b o u t th e la k e .
' T w enty-three skunks were c a p tu re d .
were a d u l t s .
F ive cau g h t p re v io u s to June 2k
Four a d u l t s , 12 ju v e n ile s and 2 o f unknown age were cau g h t
d u rin g th e rem ain d er o f th e rem oval program .
The number o f skunks cap ­
-3 1 tu r e d in c re a s e d su d d en ly d u rin g th e l a s t week o f June*
The f i r s t d a te s
(June 29, 19^1 and J u ly I , 195»2) t h a t lo n e ju v e n ile skunks were observ ed
fo ra g in g c o r r e l a t e s r a t h e r c lo s e ly w ith th e tim e o f th e in c re a s e d r a t e
o f skunk c a p tu r e .
D ata in d ic a te t h a t skunk p re d a tio n was n o t i n p ro ­
p o r tio n t o th e number o f n e s ts a v a ila b le (T able IX ).
I t a p p ea rs s i g n i f i ­
c a n t t h a t th e e a r l y n e s tin g s p e c ie s , p i n t a i l s and m a lla r d s , re c e iv e d th e
l e a s t skunk p re d a tio n (T able X ).
P o s s ib ly an in c r e a s e i n skunk a c t i v i t y
a f t e r ju v e n ile s a re a b le to le a v e th e dens acco u n ts f o r th e g r e a te r p r e - .
d a tio n on l a t e n e s t e r s .
Skunk d e s tr u c ti o n o f n e s ts was. £ l p e r c e n t g r e a te r on th e p e n in s u la
th a n on o th e r a re a s i n 195)1.
A fte r th e skunk rem oval program i n 1952,
skunk d e s tr u c tio n was 79 p e r c e n t l e s s on th e p e n in s u la th a n on o th e r
a re a s (T able "X). 'B i 1952, skunk p r e d a tio n d e c re a se d 92 p e r c e n t from '
1 9 5 l on th e p e n in s u la ; L|.0 p e r c e n t on o th e r a r e a s .
N est su c c e ss was 75 p e r c e n t l e s s on th e p e n in s u la th a n on o th e r
a re a s i n 1951.
A fte r th e skunk rem oval program i n 1952, n e s t su cc e ss
was 132 p e r c e n t g r e a t e r on th e p e n in s u la th a n on o th e r a r e a s .
B i 1952,
n e s t su c c e ss in c r e a s e d 786 p e r c e n t over 1951 on th e p e n in s u la , b u t de­
c re a s e d 3 p e r 'c e n t on o th e r aT eas.
Only two n e s ts were d e stro y e d b y skunks on th e p e n in s u la i n 1952
( J u ly 20-26) in d ic a tin g t h a t th e t r a p l i n e was s u c c e s s f u l i n p re v e n tin g
la r g e s c a le movements i n t o t h i s a r e a .
Kalmbach (1938) i n a skunk rem oval s tu d y in N o rth D akota fo u n d .3 0 .U
p e r c e n t skunk n e s t d e s tr u c ti o n and
p e r c e n t n e s t su c c e ss i n 1936
-
' T able H .
32-
Humber o f a c tiv e n e s ts u n d er o b s e rv a tio n and p e rc e n ta g e
d e stro y e d by skunk a t G re e n fie ld s t a k e , 195>1 and 1932.
1951'
1952
Ho. a c tiv e
n e s ts
U /2 7 -5 /3
I
0.0
I
0.0
5 /1 1 -1 7
I
0 .0
5/ 20-26
5 /1 8 -2 1
8
0.0
5 /2 7 -6 /2
5 /2 5 -3 1 ■
19
0.0
6 /3 -9
6 /1 -7
21
0.0
6/ 10-16
6/ 8- 1I4.
bo
■ 7»5 (3)
6/15-21
bo
2 0 .0 .(8 )
6/2 1 -3 0
6/ 22-28
36
22.2 (8)
7 /1 -7
6 /2 8 - 7 /5
bo
20.0 (8)
31
b l . 9 (13) '
lb
3 5 .7 (5)
10
5o.o (5)
5/L -io
.
6/17-23
P er c e n t skunk
d e stro y e d
7 /8 - l b
7/6-12
7 /1 5 -2 1
7 /1 3 -1 9
.
7/22-28
7/ 20-26
7 /2 9 -8 /b
3 .
8 /5 -1 1
2
33 .3 (1 )
100.0 ( 2)
-3 3 Table S .
S uccess o f la n d n e s ts on th e p e n in s u la and o th e r a re a s a t
G re e n fie ld s Lake, 195>1 and 1952.
‘ S p e c ie s
No.
N e sts
P e rc e n t
H atched
Skunk
P er c e n t D e stro y ed by
Unknown
M isc.
P re d a to r
D e s e r tio n ■
1951
O ther A reas
P in ta il
M allard
S h o v e lle r
Gadwall
B ald p ate
G. '¥. T e a l
B-. ¥ . T eal
L e s s e r Scaup
T o ta l
P e n in s u la
P in ta il
G adwall
B aldpate
G. W. T eal
B. ¥ . T eal
L e s s e r Scaup'
T o ta l
10
k
3
11
I
h
5
I
39
.
h
11
I
2
3
I
22
70,0
5 o .o
3 3 .3
3 0 .0
25.0
. 3 3 .3
6 3 .6
27.3
100.0
0 .0
0 .0
7 5 .0
20.0 . 6 0 .0
100.0
0 .0
3 5 .9 , 51 .3
■ 25.0
9.1
0 .0
0 .0
0 .0
0 .0
9 .1
5 0 .0
81 .8
100.0
100.6
100.0
7 7 .3
25 .0 .
3 3 .3
9.1
2 5 .0
20.0
' 2 .6
2 .6
7.7
25 .0
9 .1
'
100.0
Iu5
iu 5
ho5
2 3 .5
5 .9
11.8
33 .3
50 .0
50 .0
1952
O ther A reas
P in ta il
M allard
S h o v e lle r
Gadwall
B aldpate
G. ¥ . .T eal
B. ¥ . T eal
L e s s e r Scaup
Redhead
T o ta l
P e n in s u la
P in ta il
M allard
Gadwall
S h o v e lle r
B ald p ate
G. W. T eal
B. '¥. T eal
L e s s e r Scaup
T o ta l
17
6
2
2
I
6
11
2
2
■ h9 ... : .
9
3
9
I
2
3
I
3
31
. 1*7.15o.o
5o,o
11 .8
1 6 .7
5 0 .0
0 .0
0 .0 ■
5 0 .0
3 3 .3
7 2.7
9 .1
5 o .o
5o.o
. 3U.7
3 0 .6
100.0
1 6 .7
9 .1
50 .0
9 .1
12 .2
5 0 ,0
6 .1
- 77.8
100.0
100.0
100.0
0 .0
6 6 .7
0 .0
100.0
8 0 .6
1 6 .3
22.2
50.0
50.0
3 .2
9 .7
3 3 .3
100.0
6 .5
-3 h b e fo re skunk rem oval, and fo llo w in g rem oval i n 1937# skunk n e s t de­
s t r u c t i o n o f 6o5> p e r c e n t and n e s t su c c e ss .of 69.3 p e r c e n t.
He con­
c lu d e d t h a t th e in c r e a s e i n n e s tin g su c c e ss was due to r e d u c tio n o f
skunk d e s tr u c ti o n , s h i f t o f th e duck p o p u la tio n c e n te r and p o s s ib ly
some unknown f a c t o r s .
No a p p a re n t f a c t o r r e p la c e d th e skunk i n n e s t d e s tr u c ti o n on th e
p e n in s u la d u rin g 1932.
Kalmbach (1938) found a s l i g h t in c re a s e i n de­
s t r u c t i o n b y crows and r e d 'f o x e s a f t e r skunk rem o v al.
Egg su c c e ss on th e p e n in s u la and o th e r a rb a s c o rre sp o n d s i n g e n e ra l
to n e s t, su c c e ss f o r th e two y e a r s .
Egg su c c e ss on th e p e n in s u la i n 195>2
compared to 1931 and to o th e r a re a s i n 1932 d id n o t in c r e a s e as g r e a t l y
as n e s t su c c e ss (T ab les I and X I ) .
T his i s l a r g e l y a t t r i b u t a b l e to th e
more f r e q u e n t o c c u rre n c e o f undev elo p ed eggs and l a t e embryos on th e
p e n in s u la i n 1932, l3 » 3 p e r c e n t, a s compared to 1931, 0 .0 p e r c e n t. .
On o th e r a re a s th e p e rc e n ta g e o f undev elo p ed eggs and l a t e embryos a re
q u ite s im ila r f o r b o th y e a r s j 2 .8 p e r c e n t, 1931 and 3 . U p e r c e n t, 1932.
A lthough no f a c t o r ap p eared to re p la c e th e skunk i n n e s t d e s tr u c tio n
d u rin g 1932, th e s e d a ta s u g g e s t an in te rc o m p e n sa tio n (E rrin g to n , 19L6)
th ro u g h egg s u c c e ss .'
T his and th e f a c t t h a t ducks r e n e s t make e v a lu ­
a tio n o f skunk n e s t p re d a tio n d i f f i c u l t .
E e n e sts have been re p o r te d
l e s s e f f i c i e n t th a n f i r s t n e s ts (B e n n e tt, 1938; tow , 19 lt3 ).
(I9 h 9 )
Sowls
i n h i s q u a n t i t a t i v e ex p erim en ts on r e n e s tin g fo u n d "th e average
number o f eggs in f i r s t c lu tc h e s i s s t a t i s t i c a l l y g r e a t e r th a n th e number
o f eggs i n r e n e s t s " .
This su g g e s ts t h a t heavy p re d a tio n co u ld s u b s t a n t i -
-
Table IXZ.
S p e c ie s
35-
Egg su c c e ss o f la n d n e s ts a t G re e n fie ld s Lake, 1951 and 1952.
P er c e n t u n s u c c e s s fu l' from
Unknown
L ate
No. P e rc e n t
Eggs H atched Skunk P re d a to r Undeveloped Embryo M ise. D e s e rtio n
1951
O ther a re a s
P in ta il
72
M a lla rd
23
18
S h o v e lle r
HO
Gadwall
6
B aldpate
G. W. T eal 30
B. ¥ . T eal 5b
L e s se r S c. 12
TOTAL
325
P e n in s u la
28
P in ta il
90
Gadwall
B aldpate
H
G. ¥ . T eal 19
B. ¥ . T eal 21
L e s s e r S c.
9
178
TOTAL
1-952
O ther a re a s
112
P in ta il
M a lla rd
5b
18
S h o v e lle r
Gadwall
19
B aldpate
11
G. ¥ . T eal b9
B. ¥ . T eal 83
i e s s e r S c. 16
Redhead
21
TOTAL
383
P e n in s u la
P in ta il
53
Mnl I a rd
27
12
S h o v e lle r
88
G adwall
20
B aldpate
G. ¥ . T eal 2b
B. ¥ . T eal
9
L e s s e r Sc. 30
263
TOTAL
6 9 .b
78.3
5 5 .6
2b.5
0 .0
0 .0
lb .8
0 .0
3 b .8
2 3 .6
1 7 .b
3 8 .9
6 0 .9
100.0
6 6 .7
6 6 .7
100.0
52.0
2 8 .6
1 0 .0
0 .0
0 .0
0 .0
0 .0
9 .6
U 6.b
88.9
100.0
100.0
100.0
b b .6
b 6 .3
6 1 .1
0 .0
. 0 .0
3 0 .6
lb .5
6 2 .5
2 3 .8
3 3 .b
8 .0
1 6 .7
80.9
5 .6
l.b
b .3
5 .6
1 1 .8
2 .7
1
33.3
1 6 .7
1 .9
2.8
2 .5
.3
■
r*
b.o
3 .7
25.0
1 .1
100.0
5 .1
2 5.9
3 .9
.6
6.3
33.3
38.9
b 2 .l
.9
3 .7
1 .8
1 2 .5
2 .0
2 .0
1 6 .3
57.9
100.0
b9.0
7 2 .3
1 2 .0
29.5
1 3 .1
73.6
95.2
100.0
77.3
0 .0
66.7 . 33.3
0 .0 1 00.0
80.0
69.2
6 .5
1 .2
37.5
28.6
2 .6
.8
b 7 .6
8 .Ii
12.3
18.7
1 .9
1.9
3 .8
1 0.2
1 2.5
5 0 .0
5o.o
4 .2
4 .6
lb . 8
1 6 .7
1 0 .6
3.3
■ b.9
-
36-
a l l y d e c re a se p o t e n t i a l re p ro d u c tio n even i f a l l fem ales r e n e s te d
s u c c e s s f u lly .
S ince skunk p re d a tio n in c re a s e d l a t e r i n th e seaso n r e ­
n e s ts would be more v u ln e ra b le th a n f i r s t n e s t s .
BROODS
Brood o b s e rv a tio n s began June I b o th y e a rs and te rm in a te d Septem ber
1 0 , 195>1 and Septem ber I 5 1952. . The m a jo r ity o f th e broods were ob­
s e rv e d d u rin g w eekly bro o d c o u n ts made b y w alking th e s h o r e lin e o r by
b o a t from s u n r is e t o 9 :00 A. M.
Broods were c l a s s i f i e d a c c o rd in g to
s i z e a s fo llo w s : G lass I (0 -1 /3 grow n). C la ss U
H I ( 2 / 3 - f u l l grow n).
3 8 2 , 1952.
Z II.
(1 /3 - 2 /3 grow n). C la ss
A t o t a l o f 735 broods was o b serv ed : 353 i n 1951?
Broods see n and averag e s iz e b y s p e c ie s a re g iv e n i n Table
Brood ages were e s tim a te d (Hochbaum, 19llU? Southw ick3 1953) so
t h e i r h a tc h in g d a te s c o u ld be a s s ig n e d t o a 10 day p e rio d ( Table X I I I ) .
E ig h ty -fo u r p e r c e n t o f th e broods h a tc h e d from June I - J u l y 31 i n 1951?
79 p e r c e n t, 1952.
G ira rd ( l9 ltl) r e p o r te d "w ith th e e x c e p tio n o f th e
ruddy duck, th e months o f June and J u ly co v er th e h e ig h t o f th e h a tc h in g
seaso n o f ducks i n w e ste rn M ontana."
Lower te m p e ra tu re s and g r e a te r p r e c i p i t a t i o n ( Table XIV) a p p a re n tly
r e ta r d e d h a tc h in g peaks (T able X I I I ) i n 1951 as compared t o 1952.
Low
(19U5) r e p o r te d subnorm al te m p e ra tu re s , e x cess p r e c i p i t a t i o n and e x cess
c lo u d y days d e la y e d th e re d h e ad i n m ig ra tio n and egg la y in g . • Tocum
(1950) found a p o s i t i v e c o r r e l a t i o n betw een h a tc h in g o f w a terfd w l and
m e te ro lo g ic a l c o n d itio n s .
Average C la ss I I I ' b ro o d s iz e was g r e a te r th a n C la ss I i n some c a s e s .
-37Table Z H .
S p e c ie s
P in ta il
195>1
1952
G adwall
1951
1952
L e s s e r S c.
1951
1952
M allard
1951
1952
B ald p ate
1951
1952
S h o v e lle r
1951
1952
G. "W. T eal
1951
1952
B. ¥ . T eal
1951
1952
Redhead
1951
1952
Canvas-rback
1951
1952
Ruddy Duck
1951
1952
T o ta l
1951
1952
Number and average s iz e o f b roods o b serv ed a t G re e n fie ld s
E ake5 195>1 and 195)2.
C la ss I
Number Average
Broods
S iz e
C la ss IX
Number Average
Broods
S iz e
C la ss I I I
Number Average
Broods
S iz e
T o ta l" .
Broods
36
3k
H M l- 7 )
6 .2 (1 -1 0 )
38
36
12
I . 1 (1 -9 )
6 .9 (2 -1 0 ) • 11
5 .l( 2 - 8 )
6.8 (3 -1 0 )
116
111
h2
k2
7 .0 (1 -1 0 )
7 .7 (1 -1 2 )
6 .9 (1 -1 1 )
7 .6 (3 -1 2 )
7
21
6.M 5-9)
7 .9 (3 -1 2 )
100
117
18
37
6 .5 (3 -1 2 )
6 .9 (1 -1 0 )
51
51
20
27
7 .1 (3 -1 2 )
7.5 (5 -1 0 )
I
•18
5 .o
8 .3 (7 -1 0 )
39
82
I
7
•
h
h
7 .3 (6 -1 0 )
7 .1 (5 -1 0 )
6
5
7.5 (5 -1 1 )
6 .2 (3 -1 0 )
6
3
5 .2 (3 -7 )
8 .7 (7 -1 0 )
16
■ 15
6 .0 ( 1 —8)
5 .5 ( 3 - 7 )
l"
6 .0
I
6 .0
11
2
6 .2 (1 -1 3 )
3 .5 (2 -5 )
•I
I
7.0
7 .0
I
8 .3 (8 -9 )
I
7 .0
I
8 .0
3
I
■ 2
8 .0
8 .0
27
18
I . 5 .0
I
6
12
7
11
13
7 .7 (1 - 9 )
8 .5 (5 -1 0 )
9
11
6 .l( l- 9 )
1 .0 (2 -7 )
8
I
5 .9 ( l- 9 )
7 .0
17
12
2
2
1 .0 (1 -7 )
2 .5 (2 -3 )
3
2
3 .3 (1 -5 )
3 .0
5
I
7 .2 (5 -1 0 )
5 .5 (5 - 6 )
7
6 .1 (1 -1 1 )
10
2
1U7
155
6 .2
6 .7
15
3
7 .1 (3 -1 1 )
6 .3 (5 -8 )
7 .0
17
3
56 ' 5 .3
96
7 .5
352
382
I
'119 ■ 6.2
7 .2
131
‘
■
■—3 8Table S I I T .
S p e c ie s
H atching d a te s o f b ro o d s o b serv ed a t G re e n fie ld s Lake, 1931
and 1932.
May June June June J u ly J u ly J u ly Aug. Aug.
May May
1-10 11-20 21-31 1-10 11-20 21-30 1-10 11-20 21-31 1-10 11-20
P in ta il
1931
1932 ’
3
Gadwall
1931
1932
M allard
1931
1932
S h o v e lle r
1931
1932
B ald p ate
1931
1932
B. "W. T e a l '
1931
1932
G. W. T eal
1931
1932
L e s se r S c .
1931.
1932
G anvas-back
1931
1932
Redhead
1931
1932
Ruddy Duck
1931
1932
TOTAL
1931
1932
3
18
10
23
148
10
22
13
12
7
Tl
3
2
2
I
k
13
7
29
16
18
29
10
10
lit
I
I
3
3
3
3 •
■3
h
2
I
2
3
I
I
2
3
2
3
2
3
1 ,
7
2
3
3
13
I
.
I
3
I
I
3
3
I
■ 2
1
I
2
18
13
29
30
13
39
h6
3
I
I
2
I
3
1
3
2
6
I
I
h
10
3
Hi
10
9
3
7
I
I .
2
2
I
I
2
3
I
3
1
I
3
2
2
I
I
3
I
3
2
it
2
28
62
3l
Mt
60
27
22
28
28
10
8
-3 9 Table S IV .
Month
Average p r e c i p i t a t i o n and te m p e ratu re a t F a i r f i e l d ,
M ontana, 1931 and 1932.
Average Temp.
°F .
1951 1952
D ep artu re
Normal
1951 1952
P r e c i p i t a t i o n D ep artu re
i n in c h e s
Normal
1952
1951
1951 1952
2 8 .2
A p r il
ItO.3
lt9.lt
• - 3 .1
May
3 2 .0
5 3 .9
June
3 3 .0
59.7
Table ZV.
Average c lu tc h s iz e arid eggs h a tc h e d o f s u c c e s s f u l net
a t G re e n fie ld s L ake, 1951 and 195.2.
.33
.29
i
2 0 .3
q
March
- .2 7
6 .0
.51t
.2 3
- .2 2
- .5 3
0 .0
1 .9
l.ll2
1 .8 7
- .3 6
.09
- 6 .2
0 .5
2.8 6
!.lit
- .1 1 -1 .8 3
—1 1 .7 -IteO
S p e c ies
Number
N ests
Hatched-
Average
C lu tc h
. S iz e
P in ta il
Gadwall
L esser"S caup
M allard
S h o v e lle r
G. W. T eal
B.
T eal
Redhead
C anvas-back
Ruddy duck
31
13
15
20
it
it •
2
lit
2
3
7 .5
9 .8
9 .5
9 .1
1 0 .1
8 .3
io .5
1 0 .9
1 0 .0
8 .7
Av. No.
Eggs
H atched
6 .7
8 .0
8 .5
8 .1
9 .5
7 .8
' 1 0 .0
5.U
it.5
5 .3
T his may in d ic a te fem ales lo s in g s m a lle r "broods o r b roods o f 2 o r more
fe m a les com bining.
From o b s e rv a tio n s o f broods w ith e x c e s s iv e numbers
and mixed s iz e c la s s e s th e y were known to com bine.
A ll "obvious" com­
b in e d broods were n o t in c lu d e d i n th e b ro o d d a ta .
Average brood s iz e was g r e a te r i n 195>2 th e n i n 19^1 •
This was
e s p e c i a l l y a p p a re n t i n p i n t a i l s , g a d w a lls , and l e s s e r s c a u p s , p o s s ib ly
because o f l a r g e r numbers o b serv ed .
The f a c t t h a t th e p i n t a i l h a tc h in g
peak i n 19!?1 c o in c id e d w ith a p e rio d o f ab n o rm ally c o ld and w et w eath er
p ro b a b ly a cc o u n ts f o r th e sm a ll b ro o d s as compared to 195>2.
The average number o f eggs h a tc h e d p e r s u c c e s s f u l n e s t ( Table "XV}
compared to average brood s iz e (T able X II) i n d ic a te s t h a t ju v e n ile
m o r t a l i t y was s l i g h t .
.
J u v e n ile m o r t a l i t i e s o b serv ed d u rin g 195)1 and
.
.
.
1952 w ere: 6 C la ss I ju v e n ile s dead from unknown c au se s on th e s h o r e lin e
/
and is l a n d s j 21 C la ss I ju v e n ile s dead i n n e s t s , p o s s ib ly h a tc h e d a f t e r
th e fem ale l e f t n e s t and d ie d o f e x p o su re .
Minor o u tb re a k s o f b o tu lis m
i n 1951 and 1952 may have a f f e c t e d some j u v e n i l e s .
P a s t re c o rd s in d ic a te
t h a t m ajor o u tb re a k s have o c c u rre d , th e l a s t b e in g i n 19U2.
Broods w ere found i n c a t t a i l s , a l k a l i b u lr u s h , and s m a ll bays
b a r r e n o f em ergent v e g e ta tio n .
Broods on th e la k e g e n e r a lly swam from
th e s h o r e lin e i n t o open w a te r t o escap e th e o b s e rv e r; th o se i n th e marsh
swam in to c a t t a i l c o v e r.
HUNTING SEASON
H unter u t i l i z a t i o n was o b ta in e d by p e r s o n a l in te rv ie w s i n th e f i e l d
(165 p a r t i e s ) and by p o s t a l q u e s tio n n a ir e s l e f t on c a r s (17 p a r t i e s ) ,
-la O ct. 12-Nov. l 8 j 19^1•
S upplem ental in fo rm a tio n was o b ta in e d from a
checking s t a t i o n o p e ra te d by th e Montana F is h and Game D epartm ent.
The w a terfo w l h u n tin g season e x ten d e d th ro u g h £0 c o n se c u tiv e d ay s,
O ct. 12-Nov. 3 0 .
W ith th e e x c e p tio n o f opening day , h u n tin g p re s s u re i n
O ctober was a p p ro x im a te ly h tim es as g r e a t on w eek-ends as on week d ay s.
The number o f p a r t i e s p r e s e n t , average p a r t y s i z e , and h o u rs h u n ted a re
g iv e n i n T able YVI.
K i l l f ig u r e s in c lu d e r e p o r te d c r ip p lin g l o s s which
was 26 p e r c e n t o f th e k i l l .
K i l l p e r h u n te r was s l i g h t l y g r e a te r on
w eek-ends th a n week d a y s5 k i l l p e r h o u r s l i g h t l y l e s s .
The k i l l p e r
h u n te r and h o u r was ab o u t 2 l /2 tim es as g r e a t on opening day as th e
sea so n a v e ra g e .
Of th e h u n te rs checked, 7®7 p e r c e n t had l i m i t bags
(5 d u c k s); 3 5 .2 p e r c e n t o f th e se were on opening day .
The day b e fo re th e sea so n opened s p e c ie s co m p o sitio n o f an e s tim a te d
10,300 ducks was: m a lla r d s , $0 p e r c e n t; p i n t a i l s , 1 0; b a ld p a te s , 6 ; b lu e w inged t e a l s , 6 ; g a d w a lls, 5 ; green-w inged t e a l s , U; s h o v e ll e r s , 3 ;
c a n v a s-b a c k s, 9; ru d d y d u ck s, Iij m isc e lla n e o u s ducks, 2 .
The s p e c ie s c o m p o sitio n o f 2^0 ducks checked th e f i r s t th r e e days .
w as: m a lla rd s , 37»2 p e r c e n t; p i n t a i l s , l l u 8 ; b a ld p a te s , 3 =6 ; blu e-w in g ed
t e a l s , 9 . 2; g a d w a lls ,' 1 3 . 2 ; green-w inged t e a l s , 6 . 8 ; s h o v e ll e r s , 1 0 . 0 ;
c a n v a s-b a c k s, 1 . 2 ; ruddy d u c k s, .U; o th e r ducks, 1 . 6 .
Assuming t h a t th e s p e c ie s c o m p o sitio n rem ain ed r e l a t i v e l y c o n s ta n t
th e f i r s t th r e e d a y s, p i n t a i l s , b lu e-w in g ed and green-w inged t e a l s com­
p osed "a s l i g h t l y g r e a t e r p e rc e n ta g e o f th e bag th a n o f th e p o p u la tio n .
G adw alls and s h o v e lle r s o c c u rre d 2-3 tim es more f r e q u e n tly i n bags th a n
Table ZVX„ Hunter u se and su c ce ss a t G reen field s Ia k e 5- 195>1«
Item s
Season
T o ta l
Opening
Day
WeekDays .
HOVEMBER
A ll
Days
6
11
u*
211
102
19
100
1*9
8
2 .1 1
1.8 8
2.38
3 .6 3
2.9 7
6 .0 2
I . Olt
.91
1.6 8
.1*2
.36
.11
1.1*6
1 .2 7
1 .7 9
s
.1*3
%
CO
CO
Humber days
checked
• 31«!?
.2
P a r ti e s ?
p re sen t
22
38U
P a rtie s
182
checked
22
Average Ho. •
h u n te rs i n
2 .0
p a r ty
2 .0 2
Average Ho.
h o u rs h u n ted
• 3.1*8
p e r h u n te r
3 .2 7
.Average Ho.
ducks i n bag
3 .3 0
p e r h u n te r
1.3U
Average Ho.
ducks l o s t
p e r h u n te r
.1 2
Average k i l l
I*.18
p e r h u n te r
1 .7 9
Average k i l l
1 .2 0
.20
p e r hour
9
- D eterm ined b y c o u n tin g c a r s .
OCTOBER
S a t. & Sun.
(w eek-ends)
•rh3~
i n th e p o p u la tio n .
B a ld p a te s and o th e r ducks p e rc e n ta g e o f bag was
a p p ro x im a te ly t h a t o f th e p o p u la tio n ; m a lla r d s , l e s s .
G anyas-backs and
ru d d y ducks composed l i t t l e o f th e bag in p r o p o r tio n to p o p u la tio n
p r e s e n t.
The f a c t t h a t p r a c t i c a l l y a l l h u n tin g was done on th e s h o re lin e
and th e r e a re no good p a s s e s on th e la k e p ro b a b ly acco u n ts f o r th e sm a ll
number o f d iv e r s bagged.
S p e c ies co m p o sitio n o f 5>01 ducks exam ined i n h u n te r s ’ bags d u rin g
th e season was: m a lla r d s , 37»8 p e r c e n t; p i n t a i l s , lU ; g a d w a lls , '1 1 .6 ;
s h o v e ll e r s , 9 .8 ; b lu e-w in g ed t e a l s , 6 .2 ; green-w inged t e a l s , £ .8 ; b a ld p a t e s , lj.e2; l e s s e r s c a u p s , 3 .2 ; c a n v a s-b a c k s, 2 .0 ; re d h e a d s , 1 .6 ; o th e r s ,
UeO .
Of 85 geese exam ined, 7 7 .6 p e r c e n t were l e s s e r snow; 2 0 .0 , Ross
( Chen r o s s i i ) ; 1 .2 , w h ite - f r o n te d (A nser a lb if r o n s f r o n t a l i s ) ; 1 .2 ,
Canada.
A fte r s e v e re w eath er i n l a t e O ctober and e a r l y November th e la k e
was i c e covered w ith th e e x c e p tio n o f s e v e r a l s m a ll a r e a s .
F ollow ing
t h i s , m a lla rd s were e s tim a te d t o compose a t l e a s t 95 p e r c e n t o f the
p o p u la tio n f o r th e re m a in d e r o f th e s e a s o n .
M allard h a b its o f r e s t i n g
i n s m a ll open a re a s o f th e la k e and fe e d in g i n f i e l d s e a r l y m orning and
l a t e evening h o u rs was n o t conducive t o h u n tin g on th e l a k e .
They
fu r n is h e d some h u n tin g i n f i e l d s and e x c e lle n t h u n tin g d u rin g in c le m en t
w e ath e r when th e y took re fu g e i n d ra in a g e d itc h e s on i r r i g a t e d farm
la n d s .
M a lla rd s g e n e r a lly fe d i n h a rv e s te d g r a in f i e l d s .
Only two u n ­
h a rv e s te d f i e l d s o f s m a ll g r a in were known to have been damaged by fe e d -
-I lii-
in g m a lla rd s and a few p i n t a i l s ,
P r a c t i c a l l y a l l f i e l d s had been h a r v e s t-
e d Tdien t h i s damage o c c u rre d .
S IM R Y
1.
A s tu d y t o d e term in e w a te rfo w l r e l a t i o n s h i p s to G re e n fie ld s E ake5
P a i r f i e l d 5 M ontana5 was conducted May 9 to November 3 0 5 1951 and May
28. to Septem ber 2.05 1952.
In fo rm a tio n on s p rin g m ig ra tio n was s e ­
cu red d u rin g w eek-ends i n M arch5 A p r il5 and May5 1952.
2.
The la k e h a s an a r e a o f It5IOO a c r e s ; maximum d ep th o f 9®6 f e e t ;
sh o re l i n e o f 21.88 m ile s .
and wigeon g r a s s .
r in g i n q u a n t i t i e s .
I t h a s ab u n d an t. grow ths o f sago pondweed
A lk a li b u lru s h i s th e o n ly em ergent s p e c ie s o c c u r­
A c a t t a i l marsh o f 360 a c r e s , co n n ected t o th e
la k e w ith a l / 2 m ile d ra in a g e d i t c h , su p p o rts th e o n ly s u b s t a n t i a l
s ta n d o f em ergent c o v e r.
3.
Lake shore v e g e ta tio n was o f th r e e main ty p e s : greasew ood, 39 p e r
c e n t (8.5U m ile s ) ; g r a s s , 52. U p e r c e n t (1 1 .Ij6 m ile s ) ; a g r i c u l t u r a l
la n d , '8 .6 p e r c e n t (1 .8 8 m ile s ).'
U.
N in e tee n s p e c ie s o f w a terfo w l u t i l i z e d th e a re a d u rin g th e s p rin g
m ig r a tio n , e x te n d in g over an e s tim a te d 98 d a y s.
P i n t a i l s had th e
m ost b a la n c e d sex r a t i o (107:100) o f th e p u d d le rs ; s h o v e l l e r s , most
u n b a lan c e d ( 293: 100) ; red h ead s had th e m ost b a la n c e d se x r a t i o
(l3 lj:1 0 0 ) o f th e d iv e r s ; c a n v a s-b a c k s, m ost u n b alan ced (U 02:100).
5.
C ounts o f t e r r i t o r i a l p a i r s and lo n e m ales in d ic a te d a b re e d in g popu­
l a t i o n o f 3Ul p a i r s o f 12 s p e c ie s on th e la k e i n 1952.
Greasewood
s h o r e lin e s u p p o rte d 55 p e r c e n t o f th e t e r r i t o r i e s ; g r a s s , IjO; a g r i ­
~k5-
c u l t u r a l Ia n d 7
E r r e g n l a r i t y o f s h o r e lin e , p re se n c e o f s m a ll i s ­
la n d s , and b a sh e s r e s t r i c t i n g v is io n were f a c to r s w hich may have
been re s p o n s ib le f o r th e g r e a te r d e n s ity o f t e r r i t o r i a l p a i r s along
th e greasew ood s h o r e lin e .
6.
A t o t a l o f 222 a c tiv e n e s ts o f 11 s p e c ie s was f o u n d ,.107 i n 19^1 and
115) i n 195)2.
L o c a tio n s o f n e s ts were a s fo llo w s ; greasew ood, 115>;
i s l a n d s , U3; em ergent v e g e ta tio n , 38; g r a s s , 26.
7.
H atching su c c e ss o f 5)03 eggs from la n d and lj.69 eggs from w a te r n e s ts
was 2 3 .8 and Iii?.8 p e r c e n t r e s p e c t i v e l y i n 1931.
P re d a tio n caused
th e f a i l u r e o f 6 9 .8 p e r c e n t o f eggs from la n d n e s t s and 3 .0 p e r c e n t
o f th e eggs from w a te r n e s t s .
8.
H est su c c e ss i n 1931 was 26.2 p e r c e n t f o r 6l la n d n e s t s a id 69.7 p e r
c e n t f o r I46 w a ter n e s t s .
S tr ip e d skunks were r e s p o n s ib le f o r . t h e
g r e a t e s t d e s t r u c t i o n , 6 0 .7 p e r c e n t o f la n d n e s ts and Lu3 p e r c e n t o f
w ater n e s t s .
W ater was an e f f e c t i v e skunk b a r r i e r a s in d ic a te d by
th e m inor p r e d a tio n on w a te r n e s t s .
9.
From A p r il 6 to August 2 , 1932 an e x p erim en t was co nducted on th e
e f f e c t o f skunk re d u c tio n upon su c c e ss o f la n d n e s t s .
Skunk de­
s t r u c t i o n d e c re a se d 92 p e r c e n t from 1931 on th e c o n tr o lle d a re a ;
I4.O p e r c e n t on o th e r a re a s n o t c o n tr o lle d .
H est su c c e ss in c re a s e d
786 p e r c e n t ov er 1931 on th e c o n tr o lle d a r e a , b u t d e c re a se d 3 p e r
c e n t on o th e r a r e a s .
A lthough no f a c t o r ap p eared to r e p la c e th e
skunk i n n e s t d e s tr u c ti o n , d a ta s u g g e s t an in te rc o m p e n sa tio n th ro u g h
egg su c c e ss
10.
A t o t a l o f 735 broods was o b se rv e d , 353 i n 1951 and 382 i n 1952*
E ig h ty -fo u r p e r c e n t h a tc h e d June I to J u ly 31 i n 1951; 79 p e r c e n t
i n 1952*
Lower te m p e ra tu re s and g r e a t e r p r e c i p i t a t i o n a p p a re n tly
r e ta r d e d h a tc h in g peaks i n 1951*
Average brood s iz e was g r e a t e r i n
1952 th a n i n 1951*
11.
H unter c o n ta c ts p ro v id e d in fo rm a tio n on h u n te r u t i l i z a t i o n and
su ccess.
K i l l p e r h u n te r and h o u r was ab o u t 2*5 tim es as g r e a t on
opening day as th e se a so n a v e ra g e .
p e r c e n t o f th e k i l l .
R ep o rted c r ip p lin g lo s s was 26
Of h u n te rs checked, 7*7 p e r c e n t had l i m i t
bags o f 5 ducks; th e av erag e was 1 .8 .
F iv e .s p e c ie s o f p uddle ducks
made up a- g r e a te r p e rc e n ta g e o f th e bag .th an o f th e p o p u la tio n ; one
ab o u t th e same, one l e s s . . D iving ducks composed l i t t l e o f th e bag
i n p r o p o r tio n to numbers p r e s e n t.
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19&2*
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19U3.
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_____ ___
1939»
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" '
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