Preys Brought Home by Free-ranging
Domestic Cats(Felis catus) in Low-altitude Village in Ping-tung, Taiwan
研究生：郭智筌 Kuo, Chih-Chuan
指導教授：孫元勳 Sun, Yuan-Hsun
哺乳類獵物裡，溝鼠(Rattus norvegeicus)和小黃腹鼠(Rattus losea)是主要捕獲物種，其次是臭鼩(Suncus murinus)；鳥類部分，主要物種是麻雀(Passer montanus)，其餘物種比例均少於10%。爬蟲類裡，紀錄到蝎虎(Hemidactylus frenatus)比例最多，其次是長尾南蜥(Mabuya longicaudata)。昆蟲類，以住家周圍的蜚蠊目被捕獲比例最多。
To determine the temporal patterns of prey composition and number brought back home by free-ranging domestic cats at low altitude villages, cat owners in seven townships in Pingtung County during December 2004 and March 2005 and in June, 2005 was investigated. Volunteers were asked to record the prey items being brought back home by their cats. Based on the results of my survey, I proposed a suggestion about how to regulate cat’s outdoor activity to reduce their impact on local wildlife.
There were 27 voluntary cat owners with 44 free-ranging cats surveyed. Among them, 23 cats were monitored for >1 year, 13 cats for 1/2 year, and eight cats for less <1/2 year. Total prey items recorded was 542, including 10 species of three orders of mammal, 17 species of five orders of birds, seven species of two orders of reptiles, two species of one order of amphibians, nine orders of insects, and five species of four orders of the others. With those cats that had been record >1 year, a total of 244 prey item were discovered. On average, a cat could hunt > 10.6 prey items per year. Of which, small mammals account for 46.31%, birds 24.18%, reptile 13.52%, insect 13.52%, amphibian 0.82%, and others 1.64% by number.
For mammals, brown rats (Rattus norvegeicus) and brown country rats (Rattus losea) were the main captured preys, while house shrews (Suncus murinus) come second. Among birds, tree sparrows (Passer montanus) were the main captured preys, while the individual percentage of other avian captured species was <10％. Among reptiles, common house geckos (Hemidactylus frenatus) were captured most often, while long-tailed skinks (Mabuya longicaudata) come second. Among insects, Blattaria around human living places were captured the most.
The composition of cats’ preys varied with seasons significantly. In spring and summer, cats brought home more preys, while in winter they brought the least number of prey items. Mammals were captured all year around and there was no significant difference among seasons. However, birds were captured more often in spring and summer. Reptiles and insects were captured more often in summer. Cats obviously caught more preys in daytime than at night. The best period for cats to hunt was 6-12 a.m. and 18-24 p.m. Mammals were caught most often in 18-24 p.m., birds in 6-12 a.m., and reptiles in the morning.
In view of results mentioned above, it was suggested that a better protection for wildlife from free-ranging is to reduce the quantity that birds and reptiles captured by cats by keeping cats from going out in daytime in spring and summer.
Key words: Conservation, pet, subtropical, exotic species, predation