Domestic Cats As Predators And Factors In Winter Shortages-Free PDF

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CATS AS PREDATORS ON RAPTOR PREY, FREQUENCYOF OCCURRENCEOF VERTEBRATEPREY IN THE DIET OF RURAL CATSI. Percent or relative proportion of prey in each group. Area Shrews moles Rodents Rabbits Birds Reptiles Amphibians. Maryland 8 65 12 14,Pennsylvaniaz 9 60 18 13,Wisconsina 2 82 5 11. Michigan3 0 9 95 9 0 2 3,Ontario Few Many Few,Missouri 4 68 12 10 5 1. Oklahoma Few Many Many Few Few Few,Texas 65 11 11 13. California 71 8 20, 1 Corn iled from Bradt 1949 Eberhard 1954 Errington 1936 Hubbs 1951 Korschgen.
1957 Lf ew 11yn and U r 1952 McMurry and Swrry 1941 Parmalee 1953 and Toner 1956. 2 Based on analysis of s nach contents,3Based on observed predation. MATERIALS AND METHODS, The Study Site The hunting grounds of the cats centered around our home in fal. low farmland near the village of Cobden Union County southern Illinois The area is. one of uplands known as the Shawnee Hills or Illinois Ozarks which run east to west. between the floodplains of the Mississippi and Ohio Rivers This rolling country was. once dominated by forest but now hosts orchards cultivated crops old field succession. pastures second growth deciduous woods and impoundments that at many points in. tercept the natural watersheds, Characteristically the area is dotted with small farms of which my home plot in. llS R lW Section 19 Union County is typical The house stands atop a knoll 0 3. mi from the nearest surfaced road and dwelling of a neighbor An acre of lawn and. an aged grove of conifers Tsuga Pinus Juniperus and deciduous hardwoods Quer. cw Fraxinus Acer Juglans Carya Liquidambar Liriodendron surround the house. a barn is close by Apple and nectarine Pyres orchards about 50 acres old fields. 25 acres woods 15 acres and several impoundments compose the adjacent habitats. Ground cover in the fields and orchards agree in general composition but differ in. height as a result of differential mowing In 1968 1971 annual and sometimes biannual. mowing occurred on about 75 percent of the total field and orchard acreage The woods. on the plot skirt the fields one forest like stretch extends up a ravine to within a few. feet of the barn, The Mammalian Fauna The three cats had merely to step out of the barn or off the. lawn to enter habitats containing 18 species of possible mammalian prey Table 2 in. cluding three microtines seven other rodents three shrews and the cottontail Oh. servations a program of can trapping for shrews George MS and specimens caught. by the cats indicated the summer abundance of these species approximated that re. ported by Hoffmeister and Mohr 1957 and Layne 1958 shown in Table 2. THE WILSON BULLETIN December1974,vol 86 No 4, OCCURRENCE AND SUMMER ABUNDANCE OF SMALL TERRESTRIAL MAMMALS EXCLUDING.
CARNIVORES AND THEIR STATUS AS PREY OF WINTERING HAWKS NEAR COBDEN UNION. COUNTY SOUTHERN ILLINOIS,Winter status as prey for. Summer Red,abun tailed Marsh American,Species dam Hawk Hawk Kestrel. Opossum Didelphis marsupialis C n n n,Eastern mole Scdopus aquaticus vc b b b. Long nosed shrew Sorex longirostris 4 U n n n,Short tailed shrew Blarina brevicauda vc b b a. Least shrew Cryptotis parva C n n b or n,Woodchuck Marmota mon x C n n n.
Eastern chipmunk Tamias striatus C n n n, Eastern gray squirrel Sciurus carolinensis U a or b b n. Eastern fox squirrel Sciurus niger U a or b n n,Southern flying squirrel Glaucomys volans U n n n. White footed mouse Peromyscus leucopus 3 VC b b b,Southern bog lemming Synaptomys cooperi U b b b. Prairie vole Microtus ochrogaster vc a a a,Pine vole Micro us pinetorum C a a or b a or b. Muskrat Ondatrazibethicus U b or n n n,House mouse Mus musculus C b a or b a.
Meadow jumping mouse Zapus hudsonius U n n n,Eastern cottontail Sylvilagus jloridanus VC a h n. 1 vc very common c common u uncommon,2 a major b minor n negligible. 3 Strongly crepuscular nocturnal,4 Rare in most of southern Illinois. i Taken frequently by owls but seemingly not often by hawks. 6 Winter hibernator, Non feline Predators The study plot was ranged over by the following native preda. tors which to a greater or lesser extent competed with the cats for prey the year. round except as noted various snakes winter hibernators Red tailed Hawk Marsh. Hawk winter visitant American KestreI Screech Owl us asio Great Horned. Owl Bubo virginianus Barred Owl Strix maria Long eared Owl Asia otus winter. visitant Loggerhead Shrike Lanius Zudovicianus raccoon Procyon lotor gray fox. Urocyon cinereoargenteus red fox Vulpes fulva domestic dog Canis familiaris. and perhaps striped skunk Mephitis mephitis The long tailed weasel Mwtela. jrenuta and mink IM vison have been recorded in nearby areas but not on the study. site and evidence is lacking to show that short tailed shrews which elsewhere may kill. voles prey on microtines in southern Illinois,CATS AS PREDATORS ON RAPTOR PREY 387.
Human predation existed in the form of sportsmen who annually harvested gray and. fox squirrels 1 August to 15 November and cottontails 11 November to 15 January. within all but the inner core six acres of the study plot A minor amount of trapping. was done by me to study the composition of the small mammal fauna but neither rodent. control nor a chemical eradication program was in effect on the study site. The Cats and Their Habits The mother cat designated Cat 1 was a brindle brought. to the study site in 1965 She weighed about eight Ibs and was sexually altered in 1967. In 1966 she gave birth to Cat 2 black female and Cat 3 gray male Both are. sexually altered with Cat 2 weighing 12 lbs and Cat 3 weighing 16 lbs Prior to the. birth of her kittens Cat 1 caught chiefly house mice depositing them in the kitchen of. my home She brought rodents and young cottontails to her young which consumed. them with relish Cats 2 and 3 began to hunt prey and their mother s prey in. creased in 1967 This expansion in predation multiplied our observations and con. firmed our impression that detailed information on predation by each member of the. group could be obtained For one thing the combined home range of the cats only en. compassed selected spots within about 17 acres of fields and three acres of woods with. parts of about five adjacent acres of field habitat being used in the late fall and winter. months Secondly the cats never ate or deposited prey where caught but instead carried. it into a delivery area consisting of the house and lawn The exclusive use of this. delivery area was verified in 18 to 70 mammal captures per cat as witnessed between. early 1967 and late 1971, The cats had all assumed definitive patterns of hunting and dietary habits before the. study began Cat 1 sought prey on only about five acres which she shared with the other. two they in turn shared the balance Cat 1 ate no prey hunting fewer hours per day. than Cats 2 and 3 each of which consumed about 90 95 percent of the microtine rodents. and cottontails that they had captured They ate varying lower percentages of their other. mammalian prey, Cat 3 was the most successful mouser This may have been due to its ability to. leap out as much as 6 to 8 feet over 3 foot high grass enabling it to reach microtine. rodents concealed in runways beneath dense cover These attacks appeared guided. mainly if not entirely by auditory and olfactory cues. Prior to 1968 and throughout the study a daily allotment per cat of 150 220 g of raw. beef chicken parts and commercial pet foods was available in the kitchen An entry. in the kitchen door enabled the cats to come and go freely between their hunting. grounds and the house All the cats slept in the house and consumed varying amounts. of the food provided for them, Recording Observed Deliveries of Prey Almost all of the outdoor portion of the de. livery area and about six acres of the cats hunting grounds were visible from inside. the house vantage points outside yielded a still wider view of the hunting grounds. Exploiting these advantages the delivery of prey was monitored from a half hour to 24. hours per day on 1 387 days during a total of about 8 500 daylight and 7 300 crepuscular. nocturnal hours Additionally 17 periods of three to 14 days involving every season in. nearly all the study years were devoted to continuous monitoring of prey deliveries. Prey items were usually weighed indoors on a fine balance scale although a small. spring scale carried outside was sometimes used Most sexing was done by external. features the counting of fetuses was done by opening obviously pregnant females before. allowing the cats to eat them The only prey the cats were not allowed to eat were. small series of voles appropriated and frozen for future sexing and or identification. December1974,THE WILSON BULLETIN vol 86 No 4, The delivery area which was rarely left unattended for longer than 48 consecutive. hours was examined and cleared of prey remains at dawn and dusk when circumstances. permitted This facilitated attribution to diurnal or non diurnal predation of some. whole and many remnant specimens stemming from unobserved deliveries Specimens. not accountable with respect to time of delivery were distributed each month between. diurnal crepuscular and nocturnal columns in proportion to the total specimens stem. ming from observed deliveries of the species Unobserved deliveries of the day shunning. white footed and jumping mice were allocated half to crepuscular and half to nocturnal. predation in accordance with the cats observed pattern of catching these species. The cats sometimes left the entrails in consuming microtines bog lemmings prairie. and pine voles and these remains were difficult to identify as to species Entrails. stemming from unobserved deliveries were allocated to species in ratio to the repre. sentation of each microtine in the total monthly captures recorded through observed. deliveries, Besides specimens completely devoured during the absence of observers gaps in my.
records and possible misleading information may have resulted from a small prey. being swallowed very swiftly and not detected by observers b the scavenging of prey. remains by opossums dogs and other animals especially at night and c failure to. find small prey or remnants concealed under leaves and grass in the delivery area. Species and Average Annual Totals of Captured Prey Mammals taken. by the three cats in the four years of study are listed in Table 3 along with. the number of fetuses killed the average weight of the prey specimens and. AVERAGE ANNUAL PREDATION COMBINED ON VERTEBRATES BY THREE CATS IN UNION. COUNTY SOUTHERN ILLINOIS 1968 1971,Number weight Percent. captured1 Of prey2 of prey2 of catch,Long nosed shrew 6 0 2 7 3 18 1 3. Eastern chipmunk 19 5 60 1150 4 0,White footed mouse 53 0 32 0 18 954 11 0. Southern bog lemming 26 5 25 662 5 5,Prairie vole 202 5 225 7 26 5265 41 9. Pine vole 72 5 26 0 23 1667 15 0,House mouse 19 5 12 234 4 0.
Meadow jumping mouse 2 5 11 27 0 5,Eastern cottontail 46 5 165 7672 9 6. Other vertebrates 35 0 38 1354 7 2,Totals 483 5 286 4 39 19003 100 0. 1 These figures are double the number of observed captured specimens see text for explanation. 2Figures are to nearest gram,CATS AS PREDATORS ON RAPTOR PREY. related data The figures for total prey are double the logged prey divided by. four This assumes the study registered 50 percent of the cats captures a. percentage roughly corresponding to 1 the average amount of total time the. the delivery area was under observation for recording prey and 2 the num. ber of prey items logged in the same year when the delivery area was under. continuous day and night scrutiny compared to the number logged during. equivalent seasonal and hourly periods when continuously scrutinized for. lesser amounts of time Figures are not available on the rate at which scaven. gers expunged evidence of unobserved deliveries If the rate was greater than. I believe the totals for captured prey given in Table 3 are low. Diurnal predation yielded 49 8 percent of the prey items crepuscular pre. dation 20 1 and nocturnal predation 30 1 percent Young cottontails con. stituted the leading prey by volume 40 percent Prairie voles were the. prey most frequently captured composing more than 41 percent of all cap. tured vertebrates and 45 percent of the captured mammals A total of 33 8. percent of the captured prairie voles plus 18 1 percent of the pine voles. contained fetuses Table 4 resulting in the average annual removal of over. 251 microtine fetuses, Potential mammalian prey not known to have been caught included all age. groups of opossum mole short tailed and least shrews muskrat woodchuck. gray fox and flying squirrels and native carnivores In addition no adults. of chipmunks or cottontails were taken nor fetus bearing bog lemmings house. mice and jumping mice, SEX RATIOS AND FETUSES IN PREY OF THREE CATS IN UNION COUNTY SOUTHERN.
ILLINOIS 1968 1971,Percentage of dissected,Average number. Prey Male Female Gravidl of fetuses,Long nosedshrew N 10 40 60 20 5 5. Eastern chipmunk N 36 44 5 55 5 0 0,White footed mouse N z 34 52 9 47 1 11 1 5 5. Southern bog lemming N 23 52 2 47 8 0 0,Prairie vole N 152 52 6 47 4 33 8 3 3. Pine vole N 33 54 5 45 5 18 1 2 0,House mouse N 13 66 6 33 3 0 0.
Meadow jumping mouse N 12 50 0 50 0 0 0, 1 Figures signify percentage of species sample not percentage of females<. cats may pose little direct threat for they are reported to kill relatively few birds in most situations Table 1 Yet as predators on rodents cats inevi tably compete for prey with many of our declining raptors and therein may lie a serious problem Cats are formidable competitors able to kill rodents at a great and rapid rate For

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