科學圖說

大冠鷲繁殖前期
(Crested Serpent -Eagles Raising Their Young)

大冠鷲是臺灣低海拔山區常見的猛禽，分佈範圍可上達中海拔山區。
因捕食蛇類，又稱為蛇鵰；胸腹間有類似梅花鹿的斑紋，也有「鹿紋」之稱，是臺灣最容易觀察到的猛禽之一。
大冠鷲經常翱翔在晴空中宣示領域，發出嘹亮悠長的鳴叫聲，每年4-5月繁殖期，臺南的淺山、丘陵地帶，常可發現牠們的巢位。
每巢產一卵，孵卵期約45天，育雛60至65天。初期幼鷹極為脆弱，曾被鳳頭蒼鷹攫走，但大冠鷲也會抓回鳳頭蒼鷹幼雛，餵食自己的幼鷹。牠們獵取食物繁雜，築巢地區因物種不同略有差異。
觀察這一巢，以蛇類為大宗，毒蛇數量不少，以赤尾青竹絲最多，還有攀木蜥蜴、石龍子、青蛙、蟾蜍、鼴鼠等。過去有親鳥抓回未死的毒蛇，反而幼鳥被蛇咬死的記錄，此次則觀察到小蛇溜下巢逃走的情形。由於巢築於樹冠層，缺乏遮蔭的樹枝，親鳥們輪流立於巢中，替幼鳥遮擋陽光，直至幼鳥羽翼豐滿為止。

The crested serpent-eagle is a common raptor in Taiwan’s lowlands to mid-elevation mountains. It feeds on reptiles, especially snakes, from where it gets its name. Markings on its underside resemble those of the spotted deer. On sunny days, it soars, announcing its territory with a clear, long call. Its breeding season is April to May. In low elevation mountains and hilly areas of Tainan, it is possible to find its nesting grounds. One egg is produced per clutch. Around 45 days are needed for hatching and 60 to 65 days for weaning. The hatchlings are weak and prone to capture by the crested goshawk. Crested serpent-eagles also prey on crested goshawk hatchlings. Snakes made up most of the diet in these nesting grounds, with the bamboo viper common. There were also Taiwan japalure, skinks, frogs, toads and moles. There have been sightings of parents bringing back live poisonous snakes, which have killed juvenile birds. I saw smaller snakes escape from a nest. The nests are in treetops with little shade and parents take turns protecting their young from the sun’s rays.