ABSTRACT Capsule: In Egyptian Vultures Neophron percnopterus, both sexes invested similar parental effort throughout the breeding period. However, there was variation in the degree of intensity of parental care during some stages of the breeding period, suggesting that sex-role specialization exists for some activities. Aims: To quantify parental care behaviour of Egyptian Vultures for the first time and to examine the role of sex, weather conditions, and stage of nesting cycle on breeding ecology. Methods: We monitored 15 nests of Egyptian Vultures to analyse parental care investment. We collected data on nine different behavioural parameters/activities per sex, which were recorded throughout the entire breeding period. Variation in parental investment was analysed using generalized linear mixed models. Results: Females invested more effort in incubation/brooding (61.45% for females and 31.54% for males) and egg turning (0.45 events/h for females and 0.37 events/h for males) while males contributed more to nest material delivery to the nest (0.67 deliveries/h for males and 0.14 deliveries/h for females). Conversely, both sexes invested the same effort in nestling attendance (21.89% for females and 21.21% for males) and food provisioning (0.28 items/h for females and 0.25 items/h for males). Furthermore, parental investment was not affected by weather, especially during critical moments such as incubation/brooding, however, changeover rate was positively related to temperature. Conclusion: Our results suggest that, in the Egyptian Vulture, one sex is not entirely responsible for a particular task and the compensatory effort of the other mate is required. Finally, our findings indicate that major events such as incubation onset and hatching caused important shifts in the patterns of parental investment.

中文翻译：

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全球濒危食腐动物的父母投资不对称：揭示性别、天气条件和筑巢周期阶段的作用

摘要胶囊：在埃及秃鹰 Neophron percnopterus 中，两性在整个繁殖期间都投入了相似的亲本努力。然而，在繁殖期的某些阶段，父母照顾的强度存在差异，表明某些活动存在性别角色专门化。目的：首次量化埃及秃鹰的父母照顾行为，并研究性别、天气条件和筑巢周期阶段对繁殖生态的作用。方法：我们监测了 15 个埃及秃鹰的巢穴，以分析父母的照顾投资。我们收集了每个性别的九种不同行为参数/活动的数据，这些数据在整个繁殖期间都被记录下来。使用广义线性混合模型分析了父母投资的变化。结果：雌性在孵化/育雏（雌性 61.45%，雄性 31.54%）和翻蛋（雌性 0.45 次/小时，雄性 0.37 次/小时）上投入更多精力，而雄性对巢材料向巢的输送贡献更大（0.67男性的分娩次数/小时，女性的 0.14 次分娩/小时）。相反，两性在雏鸟出勤率（女性为 21.89%，男性为 21.21%）和食物供应（女性为 0.28 件/小时，男性为 0.25 件/小时）方面投入了相同的努力。此外，父母投资不受天气影响，尤其是在孵化/育雏等关键时刻，但转换率与温度呈正相关。结论：我们的结果表明，在埃及秃鹰中，一个性别并不完全负责特定的任务，需要另一个配偶的补偿性努力。