降雨、繁殖月份及雛數對台灣紫嘯鶇餵食雛鳥行為之影響

Effects of Rainfall, Breeding Month, and Brood Size on Food Provision in the Formosan Whistling Thrush (Myiophoneus insularis)

本研究於2006年3～8月期間，針對新北市石碇區內的9巢台灣紫嘯鶇（Myiophoneus insularis）進行錄影。共記錄了468次親鳥餵食，雛鳥食物的辨識率為51.75%，以蚯蚓及鱗翅目幼蟲所占比例最高。雛鳥食物組成受降雨及繁殖月份影響。錄影時間內平均降雨量愈多的巢，親鳥帶回的蚯蚓比例愈高；但鱗翅目幼蟲則愈低。而於3-4月繁殖的親鳥帶回食物以蚯蚓為主；5-6月則以鱗翅目 幼蟲及蟬為主要。親鳥的餵食頻度及帶回食物大小於晴天及雨天之間沒有差別，但會受到巢中雛數影響。雛數較多的巢中，親鳥餵食每隻雛鳥的頻率顯著較低，但帶回較大的食物頻度較高。

The study was carried out in Shiding District, New Taipei City from March to August in 2006. A total of 468 feeding trips were recorded from 9 broods of the Formosan Whistling Thrush (Myiophoneus insularis) by videotaping. The nestling diet was dominated by earthworms and caterpillars, and was affected by rainfall and breeding month. As the average precipitation per hour rose during taping, the proportion of earthworm brought by parents increased, while the proportion of caterpillar decreased. Earthworm was the main nestling diet in March-April, then switched to caterpillars and cicadas in May-June. Feeding rate and prey size were affected by brood size. Feeding rate for each nestling dropped as the brood size increased, but each nestling obtained larger prey more frequently.