Ecological response of bobcats to fluctuating prey populations on the Welder Wildlife Foundation Refuge /
A natural perturbation in prey populations provided an opportunity to study changes in food habits, vegetation type use, and population characteristics of a bobcat (Lynx rufus) population on the Welder Wildlife Foundation Refuge, Texas from 1992-98. Cotton rats (Sigmodon hispidus), wood rats (Neoto...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2000.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=731980661&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A natural perturbation in prey populations provided an opportunity to study changes in food habits, vegetation type use, and population characteristics of a bobcat (Lynx rufus) population on the Welder Wildlife Foundation Refuge, Texas from 1992-98. Cotton rats (Sigmodon hispidus), wood rats (Neotoma micropus), and eastern cottontails (Sylvilagus floridanus) comprised >75% of the diet in 1993-94 based on percent occurrence. In response to a decline in these prey species, bobcats switched to other mammals, birds, and miscellaneous food items which made up >75% of the diet in 1996-97. In spring 1997-98, birds were found in 91% and 93% of the scats, respectively. Bobcats followed optimal foraging theory by increasing the number of prey items in the diet as major prey species declined in abundance. Mean annual range size of female bobcats increased from 2.3 km² during a period of high prey abundance to 4.2 km² in a period of low prey abundance. Mean annual range size of male bobcats increased from 2.7 km² to 5.8 km² as prey abundance changed. Intrasexual overlap of ranges was not evident for female bobcats during periods of high or low prey abundance. Minor vegetation type use changes occurred as prey abundance changed. Increased use of grasslands and areas around water occurred because alternate prey species were located in these areas. Bobcats preferred dense chaparral vegetation types, but spatial use of these vegetation types changed as prey abundance declined. Male bobcats dominated the collared population during high prey abundance and females dominated during low prey abundance. Number of litters and kittens decreased as prey declined, and no female bobcats were observed raising kittens during 3 years of low prey abundance. Increased dispersal and reduced reproduction resulted in lower bobcat densities. Densities of known collared bobcats increased from 9/100 km² in April 1992 to 51/100 km² in July 1994 and declined to 13/100 km² in October 1998. Survival rates decreased from 94% during high prey abundance to 44% during low prey abundance. Mortality of 2 bobcats was a result of starvation and another in poor condition was probably killed by coyotes (Canis latrans). Other causes of mortality included trapping, shooting, and automobiles. |
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| Item Description: | Vita. "Major Subject: Wildlife Science". |
| Physical Description: | xiii, 123 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 108-116). |