Timing and Variation in the Emergence and Return of Mexican Free-tailed Bats, Tadarida Brasiliensis Mexicana

本研究以觀察及捕捉取樣的方式，記述穴居性墨西哥游離尾蝠傍晚出洞及清晨入洞之時間與相對組成的變異，希望瞭解蝠群個體組成的變化（例如性別，母蝠生殖狀況，幼蝠開始覓食）對蝠群出入洞時間的影響。墨西哥游離尾蝠傍晚出洞的起始及清晨入洞的終止時間，分別與日落及日出之時間成正相關。但其在夏季中、晚期（母蝠泌乳，幼蝠開始出洞覓食）之出洞時間，相對於日落時間，顯著提前；而其清晨入洞的終止時間，相對於日出時間，亦顯著延後。捕捉取樣的結果顯示，在春末至夏末的不同時期，該蝠出入洞時，蝠群內個體組成之相對比例在時間上呈非隨機性分布。較高比例之懷孕及泌乳母蝠出現在出洞初期與清晨入洞的末期；公蝠及無生殖狀況或己終止泌乳之母蝠則呈現相反趨勢；而不論出洞或入洞，較高比例之幼蝠均出現在初期。從蝙蝠個體的能量需求、幼蝠的成長與行為發展、及蝠群受掠食壓力等角度探討，此結果支持我們的預期。

關鍵字

活動模式；蝙蝠；墨西哥游離尾蝠

並列摘要

We investigated the timing and variation in evening emergence and dawn return of a maternity colony of Mexican free-tailed bats, Tadarida brasiliensis mexicana, in the summers of 1996 and 1997. In both summers, the onset of evening emergences and the end of dawn returns correlated with sunset and sunrise, respectively. Bats tended to emerge earlier in relation to sunset during late summer than in spring to early summer. Dawn returns ended progressively later in relation to sunrise through the season. Bats emerged much earlier and ended dawn returns later in 1996 than in 1997, coincident with a severe drought in spring to midsummer 1996. Bat captures during different seasons at the cave entrance indicate that patterns of emergence and return were non-random with regard to age, sex, and reproductive classes of bats. Higher proportions of reproductive females emerged earlier in the evening and returned later at dawn. Non-reproductive and post-lactating females and males exhibited an opposite pattern. Higher proportions of juveniles tended to emerge earlier in the evening and to return earlier at dawn.

並列關鍵字

Activity patterns ； Bats ； Tadarida brasiliensis mexicana

國際替代計量

Timing and Variation in the Emergence and Return of Mexican Free-tailed Bats, Tadarida Brasiliensis Mexicana

全文下載

主題瀏覽