ABSTRACT Little is known about the biology of long-tailed cuckoos (Eudynamys taitensis). In this study, 79 dead cuckoos, mostly from the wider Auckland region, New Zealand, were examined and dissected to shed light on the sex ratio, morphology, breeding season and diet. There were no statistically significant sexual differences in the means for weight or body measurements. However, immature birds had significantly shorter bill, wing and tail lengths than adults. In adults, gonads were enlarged (for breeding) from October to January, while all cuckoos identified (from plumage) as immatures had small gonads. Of 888 food items identified from 62 gizzards, 94% were insects. The main foods were cicadas and shield-bugs (Hemiptera, 48% of food items), stick-insects (Phasmatodea, 19%) and wētās and katydids (Orthoptera, 13%). Small vertebrates (lizards and birds’ eggs and nestlings) were a minor dietary element (1% of food items; 13% of stomachs). Cicadas, stick-insects and praying mantids (large insects abundant in late summer) made up 57% of the immature diet; in adults these three categories made up just 13% of food items. Immatures leave New Zealand on migration several months after adults, and this delay in late summer and autumn coincides with an opportunity to exploit a seasonal abundance of large insects.

中文翻译：

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新西兰鸟类的尸检。2. 长尾杜鹃（Eudynamys taitensis, Aves: Cuculinae）

摘要人们对长尾杜鹃（Eudynamys taitensis）的生物学知之甚少。在这项研究中，对 79 只死杜鹃进行了检查和解剖，主要来自新西兰奥克兰地区，以揭示性别比例、形态、繁殖季节和饮食。体重或身体测量的平均值没有统计学上显着的性别差异。然而，未成熟的鸟类的喙、翅膀和尾巴的长度明显短于成年鸟类。在成人中，从 10 月到次年 1 月，性腺扩大（用于繁殖），而所有（从羽毛上）鉴定为未成熟的杜鹃都有小性腺。在从 62 种肫中鉴定出的 888 种食物中，94% 是昆虫。主要食物是蝉和盾蝽（半翅目，占食品的 48%）、竹节虫（Phasmatodea，19%）和 wētās 和 katydids（直翅目，13%）。小型脊椎动物（蜥蜴、鸟蛋和雏鸟）是次要的饮食元素（1% 的食物；13% 的胃）。蝉、竹节虫和螳螂（夏末盛产的大型昆虫）占未成熟食物的 57%；在成人中，这三类仅占食品的 13%。幼虫在成虫数月后离开新西兰迁徙，夏末和秋季的这种延迟恰逢利用季节性丰富的大型昆虫的机会。