Dispersal and Mortality of Red Foxes
Author(s): R. L. Phillips, R. D. Andrews, G. L. Storm, R. A. Bishop
Reviewed work(s):
Source: The Journal of Wildlife Management, Vol. 36, No. 2 (Apr., 1972), pp. 237-248
Published by: Allen Press
Stable URL: http://www.jstor.org/stable/3799056 .
Accessed: 06/02/2012 09:10
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .
http://www.jstor.org/page/info/about/policies/terms.jsp
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact support@jstor.org.
Allen Press is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Wildlife
Management.
http://www.jstor.org
OF REDFOXES
AND MORTALITY
DISPERSAL
lowa ConservationCommission,Boone1
R. L. PHILLIPS,
lowa ConservationCommission,ClearLake
R. D. ANDREWS,
G. L. STORM,Departmentof Ecologyand BehavioralBiology, Universityof Minnesota,Minneapolis
R. A. BISHOP,lowa ConservationCommission,ClearLake
Abstract: Duringthe periodfrom 1963 to 1968, 926 red foxes (Vulpes fulva) were capturedat dens
ear-tagged,and releasedat the pointsof capturein IowaandIllinois. Tag returnsfrom367 markedfoxes
provideddata concerningdispersaland mortality.Somejuvenilesapparentlybegin to dispersefromie
natalareain late Septemberand earlyOctober.The averagestraight-linedistancesbetweenreleasesites
and recoverysites were 18.4 miles and 6.2 milesfor 171 juvenilemalesand 124 juvenilefemales,respectively. Fourteenjuvenilemalesand one juvenilefemale were recoveredmore than 50 miles from their
natalranges. Locationsof recaptureswere not randomlydistributed(P < 0.05) with respectto direction of travel. The MississippiRiverappearsto act as a barrierto foxes that disperseon eitherside of it
in Iowaand Illinois. Huntingand trappingaccountedfor about80 percentof the mortalityof the foxes
recoveredin this study. Annualrecoveryratesfor taggedfoxes rangedfrom22 to 44 percentin Iowa
of foxes to huntingappearsto be interrelatedwith
and from18 to 35 percentin Illinois. Vulnerability
snowcoverand land use in localareas.
Dispersal-typemovementsof red foxes
havebeenreportedby ErringtonandBerry
(1937), Sheldon(1950,1953), Arnoldand
Schofield(1956), Longley (1962), Ables
(1965), Marcstrom(1968), and Jensen
(1968). Their studies provided ample
evidencethatred foxescommonlymove15
to 20 milesfromtheirnatalrangesand that
a few individualsdispersemore than 100
miles. Publishedreportsdo not, however,
providedataon suchaspectsof dispersalas
seasonaltiming,travelroutes,ratesof moveof juvenilesandadultsof
ments,proportion
each sex that disperse,and factorsassociated with initial and terminalphasesof
dispersal.
The types and extentof mortalityin fox
populationsundoubtedlyvary with area,
season, weathercondition,and unknown
factors.Differencesin mortalityratesmay
alsorelateto differencesin ratesof dispersal
in localregions.To ourknowledge,no one
has undertakenan intensivestudy of the
natureof mortalityin redfox populations.
This paper presents preliminarydata
1 Present address: Bureau of Sport Fisheries and
Wildlife, Forestry Sciences Laboratory, Missoula,
Montana.
concerningdispersaland mortalityof red
foxesin Illinois,Iowa,andMinnesota.
This study was financedby the Iowa
by NIHTraining
Commission,
Conservation
andby theU. S.
GrantNo.5 TO1GMO1779,
(CO0-133246)
AtomicEnergyCommissilon
directedby Dr. J. R. Tester. Preliminary
work in Illinois was supportedby PHS
GrantNo. CC00047directedby Dr. G. C.
Sanderson,IllinoisNaturalHistorySurvey.
We acknowledgethe cooperationof farmers, conservationofficers,and game managerswhoassistedin locatingfox dens. We
thankG. G. Good,G. F. Hubert,Jr.,G. E.
Hubert,K.P. Dauphin,andE. I. Eickertfor
assistancein the field, and Dr. D. B. Siniff
and JudithE. Baxterfor preparingcomputerprograms.AnnH. Jones,Drs. E. D.
KlonglanandR. B. Finley,Jr.reviewedthe
manuscript.
STUDYAREAS
Fieldworkto capture,mark,and release
and
foses was conductedin north-central
and
Illinois,andnorth-central
northwestern
Iowa ( Fig. 1) . In northwestnortheastern
ern Illinois,work centeredin Carroll,Jo
Daviess,andWhitesidecounties.Thewest237
Journal of Wildlife Alanagement, Vol. 36, No. 2, April 1972
238
FOX TAGGING AREAS
m
m
> 30 MILES
< 30 MILES
Fig 1. Fox tagging areas in lowa, Illinois, and Minnesota.
ern partsof these countiesare includedin
the Wisconsindriftlesssection of Illinois.
Slopesvaryfromgentleto steep. About40
Carroll
percentof the landin northwestern
County is woodland ( Storm 1965) . The
counties
easternpartsof the northwlestern
are under intensivecultivation,with relatively few woodlots. In north central
Illinois,workwas donein DeKalb,LaSalle,
and Kane counties. This area is characterizedby flat prairielandsused primarily
is flat
forintensiveagriculture.Topography
to gentlysloping,and thereare fewer timIllinois.
bered areasthan in northwestern
North central Iowa is under intensive
cultivationand the topographyvariesfrom
flat to gentlyrolling.Lessthanone percent
Iowa
of the areais woodland.Northeastern
hasgentleto steepslopes,andfarmlandsare
withwoodlands.About25 perinterspersed
cent of the areais in timber(Thorntonand
Morgan1959).
Foxeswerecapturedandreleasedin both
regions:
statesin two generalphysiographic
in hilly areaswith mixedfarmsand woodlotswithin30 milesof the MississippiRiver,
and in relativelyflat areasunderintensive
cultivation,more than 30 miles from the
MississippiRiver.
No attemptwas made to delternlinethe
relativenumbersof foxes. However,bounty
recordsfromIllinoisindicatedthatfox densities were higher in countiesadjacentto
the MississippiRiver than in the central
counties( Mohr1947,Chiasson1953) . Further evidence for higher fox densitiesin
countiesadjacentto the MississippiRiver
is providedby bounty recordsfor Iowa.
Bountyrecordsby countiesindicatedthat
0.8 and 2.5 foxes per square mile were
bountiedfromthe northcentraland northeasternareasof Iowa,respectively(Phillips
1970) .
work referredto in
The radio-tracking
thispaperwasconductedin CarrollCounty,
Illinois,and on the Cedar Creek Natural
History Area ( CCNHA) in east central
Minnesota.The latter area has been describedby Pierce( 1954),Brayet al. (1959),
and Rongstadand Tester( 1969) .
METHODS
The basic methodused was to capture,
mark,and releasefoxes at dens duringthe
springwhen litterswere restrictedto denning sites. The date and locationof the
for each
originalcapturesite wererelcorded
tagged fox. Later,the date, location,and
method of kill were recordedfor each
markedfox reportedto projectpersonnel.
Computerfacilities at the Universityof
Minnesotawere used to aid in analysisof
the data.
Foxeswere foundduringthe April-June
periodby locatingactivedens reportedby
officers,farmers,hunters,and
conservation
trappersfamiliarwithlocaldens;by searching fromgroundandair;andby requesting,
conthroughlocalnewspapers,information
pups
were
sites
where
fox
cerning den
present.
Foxes were chased from dens with the
use of a mechanicalwireferret( Stormand
Dauphin 1965) . Some foxes were pulled
REDFOXES* Philltps et al.
239
out of denswhen theirbody hairsbecame Table 1. Distances in miles between first and last capturesof red foxes tagged as juvenilesand recoveredduring
entangledin the wire;otherswere caught their
first year of life.
by hand or with a dip net when they
MALES
FEMALES
emergedfromthe dens. Steeltraps( Nos.1
MONTH
Number
Mean
Number
Mean
and2) placedat orneardensitesfor 1 or 2
RECAPof
Distance
of
Distance
TURED
Animals
Traveled
Animals
Traveled
nights were used to capturea few foxes
thatwerenotchasedfromdensby ferreting. April
2
0.0
5
0.0
14
0.4
5
0.1
Afterbeingmarked,eachfox was returned May
June
10
0.7
7
0.8
to the denwhereit wascaptured.
July
7
1.6
1
0.9
Metal tags were placed in the ears of August
4
2.5
4
0.9
1.1
1
1.6
each fox. Two typesof tags were used: a September 1
October
8
14.8
6
2.0
No. 681 monelmetal tag (NationalBand November 27
25.4
20
7.8
and Tag Co., Newport,Kentucky)and a December 38
21.1
27
7.8
48
25.8
32
9.0
button tag ( Nasco, Inc., Fort Atkinson, January
February 11
20.8
14
4.8
Wisconsin).Tags were stampedwith the March
1
51.5
2
10.8
appropriateidentificationso that an indi- Total
171
124
vidualwho killeda taggedfox wouldknow Mean
18.4
6.2
whereto sendthe recoveryinformation.
Radio transmitterswere attachedto 8
juvenilefoxes in Illinois and 23 juvenile were tagged in Illinois and 631 in Iowa.
foxesin Minnesotato determinewhenthey Tag returnswere obtainedfrom367 foxes
left the natal area. The equipmentde- by June 1969. These data providedthe
scribedby Storm(1965)wasusedto monitor primarybasis for determiningthe initial
radio-taggedfoxes in Illinois,and similar periodof dispersal,ratesof travel,distances
trackingdeviceswereusedto monitorfoxes anddirectionsof travel,andmortality.
in Minnesota( G. L. Storm,unpublished
Dispersal
data).
In thispaper,a movementof overS miles
Initialdispersalof juvenilefoxes appar( airline distance) between the point of ently occurredduring late Septemberor
originalcaptureand the recoverysite is early Octoberwhen most juvenileswere
considereda dispersal-type
movement.The about 7 monthsold. Our data indicated
arbitraryfigure of 5 miles is based on that juvenileswere still in the areaof the
reportedevidencethatsizesof homeranges natalden at leastthroughAugust(Table1).
of nondispersingred foxes are less than In September,only two taggedfoxeswere
S miles in diameter( Scott 1943:443444, killed an averageof 1.4 miles from their
Storm1965, Ables 1969, Sargeant1972) . nataldens. Dataobtainedfromradio-trackThe juvenileage-class(l-year or less) for ing of foxes also gave no evidenceof disthis study is from the month of birth persalbeforeOctober.Noneof six juvenile
throughMarch31 of the followingyear. foxes (five malesandone female) carrying
functionalradioslefttheirnatalareasbefore
RESULTS
October1 in Illinois,and 23 juvenilefoxes
A total of 926 red foxes (899 juveniles ( 10 malesand 13 females)radio-tagged
in
and 27 adults) were captured,ear-tagged, Minnesotastayed in their natal ranges
and releasedat or neardens duringApril- throughOctober1 (G. L. Storm,unpubJuneof 1963through1968. Of these,295 lisheddata).
240
Journal of Wildlife Management, Vol. 36, No. 2, April 1972
site; anotherwas killed November25, approximately99 miles from his natal area
AINE
DISTANCE
(Table 2). Both movedover 90 miles in
SEX
BETWEENNATAL
(ALL
RANGEANDPOINT
less
than 60 days, assumingthey did not
JWEDATE
OF RECAPTUREa
NILES)
OF KILL
(MILES)
leave the natalrangebeforeOctober1.
One juvenilemale in Illinoiswas moniMale
toreddailywithradioequipmentuntilradio
October12
14
October19
39
contactwas lost October23, 1966. Thisfox
October28
45
was
killedDecember10 by a trapper7
100
November 6
57
milesfromits birthplace(45 daysafterhe
November 8
95
November10
72
was last locatedon the natalrange).
Female
Anotherradio-taggedjuvenilemale that
November11
27
dispersed
from ie CCNHAin Minnesota
November24
26
traveledan averageof 11 miles per night
Male
November24
54
in one directionduringa S-dayperiodin
November25
99
November(G.L. Storm,unpublished
data).
November29
46
This
distance
is
approximately
equal
to
the
a All movements were made in less than 8 weeks, assuming that onset of dispersal occurred after October 1.
distancetraveledin 1 night by a resident
fox in familiarrange in late fall ( A. B.
). If
The onset of dispersalappearedto be Sargeant, personal communication
earlierin malesthan in females. By mid- dailymovementsof about11 milesin one
October,somejuvenilemaleshad traveled generaldirectionare typical of red foxes
more ian 20 miles from the natal areas. duringdispersaldistancesof 100 miles or
EightmalesrecovereddunngOctoberhad moremayeasilybe attainedduringperiods
traveledan averagedistanceof 14.8miles, of less fqan 1 month.
ccympared
with 2.0 miles for six juvenile The recoverydistancesof juvenilemales
in thisstudyrangedfrom0.0 to 101.2miles,
femalesrecoveredduringthis period.
Differencesin onsetof dispersalbetween with a meanof 18.4milesand a medianof
sexesmaybe relatedto seasonalchangesin 10.1miles ( Fig. 2 ) . Morejuvenilefemales
reproductive
activityof foxes. Venge(19S9) than juvenilemales remainedin or close
reportediat malesweresexuallymaturein to the natal rangesduringthe first year
late Novemberand December,whereas ( March31) . Eighty-twopercent of the
femalesdid not begin estrusuntilJanuary juvenilefemalesrecoveredin theirfirstyear
or February. McIntosh( 1963) reported were within10 milesof theirnatalranges.
thatthe testesof malefoxesbeganincreas- Recovery distancesfor juvenile females
ing in size about 3 monthsprior to the rangedfrom0.0 to 52.1miles,with a mean
height of ie breedingseason,but ovaries of 6.2 miles and a median of 2.2 miles
of femalesbeganto increasein size about (Fig. 2).
1 monthbeforethe peakbreedingperiod.
The tendencyfor more males than feData conceiningthe dailyrate of kave malesto leavetheirnatalareaswas evident
of dispersingfoxeshave not been reported for both young-of-the-year
and 2-year-olds
in the literature.Two of the juvenilemales (Table3 ) . Forty-nine( 78 percent) of 63
in the studytraveledmorethan90 milesby juvenilemalefoxesrecoveredin Iowa dur3ateNovember.One was killedNovember ing 196869 were takenmorethan5 miles
8 approxim-ately
95 miles fromthe release fromtheirnatal ranges. Vuringthe same
Table 2. Long-distancemovementsby juvenile red foxes
recoveredduringOchber and November.
REDFOXES* P/l illi ps
et al .
24 1
their first year of life and remainedthere
untiltheydied. Whetherdispersalas adults
was relatedto dispersalduringtheir first
year of life was not clear. Radio-tracking
studiesof foxes ( Storm196S,Ables 1969)
showedno evidenceof dispersalby adults
duringspringand summer.Thissuggested
ffiatadults,like juveniles,dispersedduring
tn
70the fall andwinter.
o
Informationon the directionof travel
duringdispersalwas providedby plotting
o
the recoverylocationsfor foxesthatmoved
ILI
SOm
more than S miles from their respective
2
N = 295
pointsof release.Thedataanalyzedto date
z
40* MALES
indicatedthat the kill locationswere not
a
FEMALES
randomlydistributed(P < 0.05) with respect to directionof travel. For example,
26
67 and 57 percentof the foxes recovered
20|
in Iowa and Illinois, respectively,were
killednorthof theirrespectivereleasesites
(Table 4). A similartendencyis evident
fromthe datareportedfor Michiganfoxes
by Arnoldand Schofield(1956), and for
0-}0 11 20 21-30 3l-40 41-so s>*o 61+
DISTANCETRAVELED(AIR MILES)
foxesin NorthDakota(Donahoo1962).
The higher proportionof tagged foxes
Fig. 2. Distoncesbetween first and lost copturesfor male
killed north of the points of releasemay
and female foxes recoveredwithin the first year of life.
reflecta tendencyfor a generalnorthward
movement
of red foxes, but evidencefor
period, 22 of 23 2-year-oldmale foxes
such
a
migration
wasnotconclusive( Butler
( taggedin 1967)wererecoveredmorethan
1951,
Macpherson
1964). Anotherreason
S milesfromtheirnatalranges.The higher
proportion,among adults, of long-range may be the relationshipbetweenweather
of foxesto
movements
wasalsoevidentamongfemales conditionsandthe vulnerability
hunting
pressure.
For
example,
foxes may
(Table 3). These data indicatedthat not
all foxesset up permanent
residenceduring be morevulnerablein areaswith abundant
X
L
60-
30-
|
nL1
X
Table 3. Proportionof lowa foxes recoveredmore than 5 miles from their natal ranges during the period of OctoberMarch,196K69, 1 and 2 years after tagging.
YEAROF
TAGGING
1968
1967
a
b
AGE
SEX
Young-ofthe-year
2-year-oldb
Male
Female
Male
Female
NUMBEROF FOXESRECOVERED
TOTAL
NUMBER
S Miles
More Than
RECOVERED
or Less
5 Miles
63
45
23
12
14
30
1
6
49
15
22
6
RANGEa
6.0-63.0
6.0-52.1
7.0-97.0
25.0-43.5
Upper and lower limits of recovery distances for foxes that moved more than 5 miles from their natal ranges.
About 1.5 to 2.0 ye;lrs old.
242
Journal of Wildlife Management, Vol. 36, No. 2, April 1972
Table 4. Directionol distributionof recoveries for foxes
that traveled more than 5 miles from their natal ranges.
TAGGING
NUMBEROF ANIMALS
ARAENADNE
DIREC- (OO_
TION 90°)
Iowa
Illinois
North
South
NW
(971°360°)
SE
(91°180°)
SW
(181°270°)
CHI_
SQUARE
VALUE
59
10
26
16
20
7
25.02**
8.64*
16.70**
36
21
126
69
.
ADJACENT TO RIVER
AWAY FROM RIVER
Northcentral
* Significant ( P < 0.05 ) .
* * Significant ( P < 0.01 ) .
snowcover. Sincesnowwas morefrequent
in regions north of our study areas, the
higherproportionof foxes killed north of
releasepointsmay reflecthighermortality
ratesratherthan greaterratesof dispersal
towardthe north.
Except for the higher proportionof
recoveriesnorthof releasepoints,the distributionof recoverylocationsin the northcentralcountiestendedto be randomlydistributed. A differentpatternwas evident
for animalstagged in countiesadjacentto
the MississippiRiver (Fig. 3). Therewas
Northwestern
lowa
Illinois
Fig. 3. Comparativepattern of dispersal for foxes tagged
and released in north-centrallowa (more than 30 miles
from MississippiRiver) and foxes tagged in northwestern
Illinois (less than 30 miles from MisssisippiRiver);interval
between concentriccircles equals 20 miles. Dots are placed
according to direction of travel; center of circle represents
tagging site.
no evidenceof tagged foxes crossingthe
MississippiRiveralongtheIowaandIllinois
boundaries,and it appearedtha,tthe river
served as a barrierto dispersalof foxes.
Theriverin thisareais generallynotfrozen
duringNovember,but slomeyears it may
be frozen and coveredwith snow by late
Decemberor earlyJanuary.
Table 5. Numberof red foxes recoveredwith respect to types of mortality,lowa and Illinois.
AGE AND
SEX
Juvenileb
Male
Female
STATE
NUMBER
RECOVERED
(ALL YEARS)
MORTALITY
TYPE
Hunting
Trapping
Road-kills
Miscellaneousa
Iowa
118
84
71 (61)
57 (66)
28
20
250
22 (19)
10 (11)
7 (6)
5 (6)
18 (15)
12 (14)
24 (86)
12 (60)
164 (66)
3 (11)
6 (32)
41 (16)
1 (3)
1 (5)
14 (6)
1 (5)
31 (12)
53
40
25 (47)
22 (55)
17 (32)
12 (30)
8 (15)
3 (7)
3 (12)
3 (7)
Male
Female
Subtotal
16
8
117
7 (44)
4 (50)
58 (50)
5 (31)
5 (50)
38 (32)
1 (6)
3 (19)
12 ( 10)
9 (8)
Total
367
222 (60)
79 (22)
26 (7)
e
Adultd
Male
Female
Subtotal
Juvenileb
Male
Female
Illinois
Adultd
40 (11)
Includes pups found dead at dens, killed at farln buildings, killed by farm machines, and dead from unknown causes.
Young-of-the-year through March 31 of the following year.
2 Percentage given in parentheses.
d Older than young-of-the-year.
a
b
RED FOXES* P7>illipset al.
243
Table 6. Numberof juvenile foxes killed by monthwith respect to type of mortality.
KILLED
NUMBEROF FOXES
Hunting
Trapping
Miscellaneousa
Road-kills
TOTAL
MONTH
Males
Females
Males
Females
Males
Females
Males
Females
January
February
March
April
May
June
July
August
September
October
November
December
42
11
4
1
2
1
2
8
25
30
14
2
1
1
2
12
17
6
3
17
13
2
3
7
10
1
3
6
2
3
-
1
2
1
3
1
-
2
10
7
2
-
5
4
5
1
-
80
25
3
7
19
17
8
8
2
14
47
65
Total
96
79
39
22
15
8
21
15
295
RECOVERIES
(27)b
(7)
( 1)
(2)
(6)
(6)
(3)
(3)
( 1)
(5)
( 16)
(23 )
Includes pups found at dens, those killed at farm buildings and by farm machines, and those dead from unknown
causes.
b Percentage of total recoveries in parentheses.
a
Thefactorsassociatedwith dispersalpat- tions concerningthe influenceof environterns in mammalsare not well known. mental factors on dispersalof red foxes
haveimplicatedexternal remainunanswered.We feel that these
Someinvestigators
causativefactors,such as high population problemsdeservefurtherstudy.
of habitat,or both
levels or deterioration
1963:78).Otthers Mortality
(Elton1927:146,Errington
have suggestedinternalcausativefactors, The data presented here concerning
suchas changinghormonelevels,as partof mortalityare based entirelyon reported
the stimulusfor long-distancemovements mortalityassociatedwith the taggedfoxes
(Slonaker1924,1927,Cahn1925,Howard recoveredduringour study. The relative
1960,Beer and Meyer1951). Manyques- importance
factors,such
of naturalmortality
Table 7. Recoveryrates of juvenile male and female red foxes. Numberin parenthesesis percentage recovered.
NUMBEROF FOSESTAGGED
TAG-
DURING
NUMBERRECOVERED
FIRSTYEAF(OF LIFE
YEAR
Males
Females
Males
Females
1966
1967
1968
39
128
166
40
107
137
17(44)
29(23)
70(42)
18(45)
23(22)
46(34)
333
284
116(35)
87(31)
68
22
56
48
16
43
21(31)
3(14)
18(32)
19(40)
4(25)
14(33)
Subtotal
146
107
42 (29)
37 (35)
Total
479
391
158(33)
124(32)
AREA
Iowa
Subtotal
Illinois
1966
1967
1968
944
Journalof WildlifeManagement,Vol. 36, No. 2, April1972
Toble 8. Vulnerabilityof juvenile and adult red foxes to
hunting and trapping (vulnerobilitymeosured by year-oftagging recoveries).
YEAR-OFFOXES
TAGGING
RATIOOF
TAGGED RECOVERIESRECOVERY
RATE ADULTTO
JWENILE
JuveJuveJuveVULNER_
Adults niles Aduks niles
Adults niles
asILITYt
14
617
3
155
21.4
25.1
1: 1.17
Vulnerability quotient or index = juvenile recovery
rate/adult recovery rate = 1.17.
8
Table 9.
lowa.
Tag recoveries by two geogrophic regions in
TAGGING
REGION
NUMBER NUMBER PERCENTOF FOXES RECOV- AGERETAGGED ERED
COVERED
Within 30 miles of
Mississippi River
54
10
19*
More than 30
miles from
Mississippi River
S77
236
41*
* Rate of recoverywas significantlydifferent (P < 0.05).
as diseases,parasites,and accidentsother
than those associatedwith man, was not
determined.
Hunting and trapping acoountedfor
about80 percentof the mortalityof foxes
recovered(Table 5 ) . These results are
similarto thosereportedby Jensen(1968)
andMarcstrom
( 1968). Eighty-twopercent
of the reportedmortalityoccurredfrorn
SeptemberthroughFebruary.Trappingof
foxes was done primarilyduringOctober,
November,December,and January.All of
the trappedfoxes were reportedlykilled
duringthesemonths(Table6).
SomefoxeswereshotduringOctoberand
November,andit appearedthatthe taking
of these animalswas incidentalto other
huntingactivity.Fox huntingin Iowa and
IllinoisoccurredprimarilyduringDecem-
ber and Januaryas was reflectedby the
high numberof tagged foxes reportedly
shot duringDecemberandJanuary(Table
6). Moremales than femaleswere killed
by huntingand trapping,but the differenceswerenot significant(Table7). The
slightlyhigherrecoveryof malesmayreflect
theirhigherdispersalrateandgreatertravel
n untamlllar
range.
Seventy-twofoxes were recovered as
adults(olderthanyoung-of-the-year),
and
only three of these were reportedlykilled
on roads. One adultwas reportedlykilled
by farm machines.These data indicated
thatmortalitydueto carsandfalmmachines
was not an importantfactor affecting
markedadultred foxes.
The rateof kill on roadwayswas higher
r
.1
.
Table 10. Numberand percentogeof foxes recovered1-3 years after tagying.
STATE
Iowa
YEAR OF
TAGGING
Total
FOXESRECOVERED
DURINGb
Year 1
Year 2
1966
1967
1968
79
235
303
617
35(44)
S2(22)
116 (38)
S(6)
36(1S)
0
1966
1967
1968
116
38
99
253
40(35)
7(18)
32 (32)
3(3)
6(16)
0
Total
Illinois
NUMBERa
TAGGED
Year 3
TOTAL
2(3)
O
°
42(53)
88(37)
116(38)
246 (40)
0
°
0
43(37)
13(34)
32(32)
88(35)
Tagged and released where captured as pups.
Number in parentheses is the percentage recovered after spring tagging; year 1 is from time of tagging through
March 31 of next year; year 2 is from April 1, 1 year after tagging through March 31 of the next year; and year 3 is
from April 1, 2 years after tagging through March 31 of the next year.
a
b
REDFOXES* Phillips et al.
245
Table 11. A comparisonof fox tag recovery rates from different areas.
LOCATION
REFERENCE
Iora
New York
Michigan
Russia
North Dakota
Sweden
Denmark
Iowa
Illinois
Erringtonand Berry (1937)
Sheldon(1950)
Arnoldand Schofield(1956)
Tchirkova( 1955)
Donahoo( 1962)
Marcstrom( 1968)
Jensen ( 1968)
This study ( 1966-68)
This study ( 1963-68)
NUMBEROF FOXES
TAGGED
236
120
37
126
179
163
17S
631
295
RECOVERY
RATE
( PERCENT
)
7a
33
54
21
25
36
31
40b
39b
aFoxes
b
tagged in this study were transported from natal dens to other release sites.
Includes recoveries to June 1969.
for juvenilesthanfor adultfoxes. Seventy- the sameforjuvenilesandadults.Ourdata
fourpereentof thismortalityoeeurreddur- indicatedthat juvenileswere 1.17 times
ing June,July,and August(Table 6). In more vulnerableto huntingand trapping
thesemonths,juvenilefoxeswerebeeoming thanadults(Table8) andwere 1.54times
less restrietedto denningsites and were morevulnerablethanadultswhenall types
likely to cross roads during exploratory of mortalitywereconsidered.
movements.It is probablethatsometagged The rateof mortaliity
of foxestaggedand
foxeswerekilledon roadwaysandwerenot recoveredin areasover 30 milesfromthe
reportedto us. Thefur of road-killed
foxes MississippiRiver appearedto be higher
is of no value duringthe summermonths, (P < 0.05) thanthatfor foxestaggedand
and road-killedanimalswere generallynot recoveredwithin 30 miles of the river
handledby man. Some foxes hit by cars (Table 9). Evidencefor lower mortality
may be throwninto ditehesby the impact ratesin the hilly and morewoodedlands
and remainineonspieuousto man. Thus, adjacentto the riverwas providedby agewe believe our data underestimatedthe structuredata (Phillips1970) thatshowed
importanee
of this type of mortality.
adult:juvenile ratios of about 1:2.6 for
Differeneesin vulnerabilityto hunting northeasternIowa and 1:5.6 for central
and trappingbetweenjuvenilesand adults Iowa. Whether differencesin mortality
were ealculatedby modifieationof a for- betweenphysiographic
regionswererelated
mulapreparedby Bellroseet al. (1961:435). to differencesin natality,incidenceof disWe assumedthat the rateat whiehhunters eases,hunting,trapping,farmingpractices,
and trappersreportedmarkedfoxes was andweatherconditionswas not clear.
Table 12. The relationshipof winter huntingconditionsto recoveryrates, pelt prices, and fox harvestsin lowa, 1966-68.
WINTER
PERIOD
NUMBEROF
JUVENILE
FOXESTAGGED
DURINGSPRING
1966-67
79
1967-68
23S
1968-69
303
aData compiled in cooperation
PERCENTAGE
RECOVERED
44.3
21.1
38.3
DAYSaW1TH
CUMULATIVEa >2 INCHES
AVERAGE
SNO\FALL
ACCUMULATION
PELT
(INCHES)
OF SNOW
PRICE
25.6
11.5
44.2
50
6
97
$5.80
$4.12
$10.39
FOX FURS
SOLDTO IOWA
FUR BUYERS
13>072
10,688
27,661
with the U.S. Department of Commerce, the Iowa Department of Agriculture, and the
Ioxva Weather Bureau at Mason City, Iowa.
246
Journalof WildlifeManagement,Vol. 36, No. 2, April1972
About30 percentof the foxestaggedas
juvenileswere recoveredduringthelirfirst
year (Table10). Annualrecoveryratesfor
taggedjuvenilefoxesrangedfrom22 to 44
percentin Iowa and from18 to 35 percent
in Illinois(Table 10).
Obviously,not all foxes killed by man
were reported. We know of entire unreportedlitters of markedfoxes killed at
den sites. Three unreportedtagged foxes
were also foundduringexamination
of fox
pelts sold to fur dealers.Recoveryratesof
taggedfoxes in this studywere similarto
thosereportedby previousworkers(Table
tionof foxesthatdisperse,iPtis obviousthat
dispersalis a majorinfluenceaffectingthe
populationdynamicsof red foxes. Knowledge of dispersalof foxes should be an
importantoonsideration
whendealingwith
the epidemiologyof diseases associated
with foxes, diseasecontrolprograms,programsdesignedto reducenumbersof foxes,
managementof foxes for economicand
recreationaluse, and evolutionlary
studies
of foxes.
Currently,
thereis littleknownaboutthe
relationshipsbetween dispersaland incidence of diseasesin foses. Someworkers
11).
have suggestedthat an increasein rabies
Recoveryrates in Iowa appearedto be in foxesduringthe fall-winterperiodmay
relatedto weatherconditionsfavorablefor be associatedwith the time of dispersal
huntingduringwintermonths.Snowcover ( Muller1966,Pitzschke1966,Ulbrich1967,
wasabundantin thewintersof 196S67 and Friend 1968) . Recent data presentedby
198W69yearsmarkedby highfoxharvests JohnstonandBeauregard
(1969)forOntario
andrecoveryrates(Table12). Duringthe showedthat 66 percentof the rabidfoxes
196748 wintertherewas littlesnowon the in late summerandfall weremalesand 65
Iowa studyareas,and a relativelylow re- percenitof the maleswerejuveniles.Since
coveryratewas experienced.
dispersalappearsto be more intensivein
Mortalit,v
in foxeswas associatedwith a malesthanfemales,thepotentialforcontact
complexset of factors. Mortalitydue to betweenfoxesis higherfor malesthanfor
hunting appearedto be related to the females,and therebymay accountfor the
amountof annuial
snowcover,anddifferent differencesin the incidenceof rabiesbemortalityrateswerenotedbetweenphysio- tween sexes. However,the role of behavgraphic regions. Thus, vulnerabilityof ioralisolatingmechanisms
in the transmisfoxes to man appearedto be interrelated sion of rabiesbetweensexes is unknown
withsnowcoverandlanduse in localareas. (Johnstonand Beaureglard
1969).
Programsto reducefox numbersin the
DISCUSSIONAND CONCLUSIONS
north-centralUnited States do not seem
ltis study indicated-iat approximatelyfeasible,and perhapsthey are not justified
70 percentof the markedand recovered at this time. Vertsand Storm(1966) rejuvenilemale foxes moved more than 5 portedthaitred foxes were neitheracting
miles from thelirnatal rangesduringtheir as reservoirsof rabiesduringthe pre-epifirst year. This figure increasedto over 200ticperiod,nor contributingto the in90 percentif the males survivedanother fections among striped skunks ( Mephitis
year. About 30 percentof ffie recovered mephitis)duringthe epizooticof the disjuvenilefemalesdispersedmorethan5 miles ease in Illinois.
in their first year, and the proportioninWith the high rate of interchangebecreasedto 50percentif thefemalessurvived tween local populationsbecause of disanotheryear. In view of the high propor- persingfoxes,it is apparentwhy programs
REDFOXES* Phillips et al.
247
) designedto flow, and ultimatelyon the evolutionof
(such as bounty payments
redueefox numbershave generallyfailed redfoxesin the Midwest,is notfullyunderto meettheirobjeetives.Evenif loealpop- stood. Furthertaxonomicsltudiesof foxes
ulationsare markedlyredueed,the vaeant shouldbe a fertilefield forfutureresearch.
areasbeeomerepopulatedwiithin1 yearby
foxes moving in from surroundingareas. LITERATURE
CITED
Ourdatashowthatmanyfoxestraveled20 ABLES,E. D. 196S. An exceptional fox moveto 40 miles to oceupynew rangesduring
ment. J. Mammal. 46 ( 1 ): 102.
1969. Home-range studies of red foxes
theirfirstyear.
) . J. Marnmal.50 ( 1 ): 10S120.
(
Vulpes
It may be that undercertaineonditions, ARNOLD,D. vulpes
A., AND R. D. SCHOFIELD.1956
new techniquesshouldbe developedand
( 1955 ). Home range and dispersal of Michigan red foxes. Michigan Acad. Sci., Arts, and
used undereloselysupervisedprogramsto
Letters Papers41(pt. 2):91-97.
reducenumbersof foxesin loealor regional BEER,
J. R., ANDR. K. MEYER. 1951. Seasonal
areas. Our data suggest that appropriate
changes in the endocrine organs and behavior
patterns of the muskrat. J. Mammal. 32(2):
eontrol measuresmay be most effeetive
173-191.
duringthe late winterandspringwhenthe BELLROSE,
AND
A. S. HAWKINS,
F. C., T. G. SCOTT,
numbersof foxesare at an annuallow and
J. B. Low. 1961. Sex ratios and age ratios
in North American ducks. Illinois Nat. Hist.
whellfew, if any,foxesaredispersing.
Survey Bull. 27 ( art. 6 ): 391474.
Furtherevideneeof the eeonomieimpor- BRAY,
ANDL. C. PEARSON.
J. R., D. B. IAWRENCE,
tance of foxes is providedby our data
1959. Primaryproductionin some Minnesota
terrestrial communities for 1957. Oikos 10
showingthatman,by huntingandtrapping,
( pt. 1 ) :3S49.
aeeountedfor 80 pereentof the reported BurLER,
L. 1951. Population cycles and color
in
Illinois
foxes,
Red
mortality.
taggedfox
phase genetics of the colored fox in Quebec.
Canadian J. Zool. 29(1) :24-41.
and Iowa, offer reereationalopportunities
CAHN,A. R. 1925. The migration of animals.
throughsporthuntingduringthe periodof
Am. Naturalist 59 (665): 539-556.
late Decemberthrough February,when CHIASSON,R. B. 1953. Fluctuations of some
Illinois fox populations. Ecology 34 (3): 617most other game hunting seasons have
619.
elosed. Foxhuntingmaybeeomestillmore DONAHOO,
D. G. 1962. Fox tagging study, North
attraetiveto huntersin futureyearsin the
Dakota. U. S. Bur. Sport Fisheries and Wildl.
12pp. Mimeo.
UnitedStatesif the numbers
north-eentral
C. 1927. Animal ecology. Sidgwick and
of o!thergame animalsdeeline. A sound ELTON,
Jackson, Ltd., London. 207pp.
managementpoliey eoneerningred foxes ERRINGTON,
P. L. 1963. Muskrat populations.
The Iowa State UniversityPress, Ames. 665pp.
shouldeonsiderthis speeies,not only as a
, ANDR. M. BERRY. 1937. Tagging studpredator,but as an importantgameanimal.
ies of red foxes. J. Mammal. 18(2):203-205.
We eoneludethat,withthe existingpopula- FRIEND,M. 1968. History and epidemiology of
rabies in wildlife in New York. New York
tions of man and foxes,the sporthunting
Fish and Game J. 15(1):71-97.
of foxes shouldbe eneouraged.We agree HOWARD,
W. E. 1960. Innate and environmental
dispersal of individual vertebrates. Am. Midwith Seott's ( 1955) eonelusionthat the
land Naturalist 63(1):152-161.
valuesderivedfromhuntingare moreeon- JENSEN,
B. 1968. Preliminary results from the
stantthanthosefromfurs.
marking of foxes (Vulpes vulpes L. ) in Denmark. Danish Rev. Game Biol. 5(4):14.
Thefaetthatno taggedfoxeswereknown
1969.
D. H., AND M. BEAUREGARD.
JOHNSTON,
to eross the MississippiRiver along the
Rabies epidemiology in Ontario. Bull. Wildl.
Disease Assoc. 5 (3): 357-370.
Iewa and Illinoisboundariessuggeststhat
W. H. 1962. Movements of red fox.
LONGLEY,
barrierto dispersal
the riveris an important
J. Mammal.43(1):107.
of foxes. Theinflueneeof dispersalon gene MACPHERSON,
A. H. 1964. A northward range
248
Journal of Wildlife Management, Vol. 36, No. 2, April 1972
extension of the red fox in the eastern
home rangeof red foxes in New YorkState.
Canadianarctic. J. Mammal.45(1):13S140.
J. Wildl.Mgmt.14( 1 ) :33 42.
1953. Returnson bandedred and gray
MARCS1R0M,
V. 1968. Tagging studies on red
foxes in New YorkState. J. Mammal.34( 1):
fox (Vulpes v.) in Sweden. ViltrevyS(4):
12S126.
103-117. ( Swedishsummary.
)
J. R. 1924. The effectof pubescence,
McINTosH,D. L. 1963. Reproductionand SLONAKER,
oestruationand menopauseon the voluntary
growth of the fox in the Canberradistrict.
activity in the albino rat. Arn. J. Physiol.
C.S.I.R.O.Wildl. Research8(2): 132-141.
68(2) :29S315.
MoHR,C. C). 1947. Majorfluctuationsof some
. 1927. The effect of the follicularhorIllinois mammalpopulaffons.Trans. Illinois
mone on old albino rats. Am. J. Physiol.
StateAcad.Sci. 40:197-204.
81( 2 ) :325-335.
MULLERJ
J. 1966. The reappearance
of rabiesin
G. L. 1965. Movements
and activitiesof
Denmark. Bulletin de l'Office International STORM,
foxes as determinedby radio-tracking.J.
des Epizootics65(1-2): 21-29.
Wildl.Mgmt.29(1 ) :1-13.
PHILLIPS,
R. L. 1970. Age ratiosof Iowa foxes.
, ANDK. P. DAUPHIN. 1965. A wireferret
J. Wildl.Mgmt.34(1) :52-56.
for use in studies of foxes and skunks. J.
PIERCE;,
R. L. 1954. Vegetationcovertypes and
Wildl.Mgmt.29( 3 ):625-626.
land use historyof the CedarCreekNatural TCHIRKOVA,
A. F. 1955. Tagging foxes. CanHistoryReservation,Anokaand IsantiCounadianWildl.Serv.,Translations
RussianGame
ties, Minnesota.M.S. Thesis. Univ. of MinReports3( 1958) :208-214.
nesota. 137pp.
THORNTON,
P. L., ANDJ. T. MORGAN.1959. T11e
PrrzscKE,H. 1966 (1965). Epizootiologyof
forest resourcesof Iowa. U.S. Forest Serv.,
rabies in Europe. Internatl.Symp. Rabies,
CentralStates Forest Expt. Sta., Forest SurSymposia Ser. Immunobiol.Standardization
vey Release22. 46pp.
1:231-236. ( S. Karger,Baseland New York.) ULBRICH,
F. 1967. Uber regelmafiigkeiten
beim
RONGSTAD,
O. J., ANDJ. R. TESTER. 1969. Moveauftretender tollwutim BezirkDresden: ein
mentsand habitatuse of white-taileddeer in
beitragzur epizootologieder tollwut. Archiv
Minnesota.J. Wildl. MgInt.33( 2 ):36S379.
fur ExperimentelleVeterinarmedezin
21(4):
SARGEANT,
A. B. 1972. Red fox spatialcharac1073-1084.( RussianandEnglishsummaries.
)
teristicsin relationto waterfowlpredation.J. VENGE,O. 1959. Reproductionin the fox and
mink. Animal BreedingAbstr. 27( 2 ): 129Wildl. Mgmt. 36(2):225-236.
145.
SCOTT,T. G. 1943. Somefood coactionsof the
northernplains red fox. Ecol. Monographs VERTS,B. J., ANDG. L. STORM. 1966. A local
study of prevalenceof rabies among foxes
13(4) :427-479.
and stripedskunks.J. Wildl.Mgmt.30(20):
. 1955. An evaluationof the red fox.
419421.
IllinoisNat. Hist.SurveyBiol.Notes35. 16pp.
SHELDON,W. G. 1950. Denning habits and Received
forpublication
April30,1971.