Asynchronous hatching is a common hatching pattern in the Little Egret Egretta garzetta, however, its role in maintaining dominance relationships and feeding hierarchy among siblings remains poorly studied. In this study, we investigated this issue using data on feeding and aggressive behaviours of Little Egrets nestlings in a southern Tunisian breeding colony. We found that senior nestlings were the first to access the food brought by their parents, and they ingested more food than their younger siblings did. Intermediate nestlings engaged the most frequently in aggression. The youngest nestlings showed a more resigned and less aggressive behaviour, therefore receiving a little less food, but much fewer pecks and injuries than their elders do. These findings stress the importance of hatching order in establishing a feeding hierarchy among Little Egret siblings. Moreover, they suggest that access to food may not be the unique factor that shapes nestlings’ feeding behaviour and competitiveness, as the avoidance of injuries caused by siblings’ attacks may be important. Finally, adult birds appeared to adopt a ‘laissez faire’ strategy, showing no feeding favouritism to counteract or reinforce the effects of hatching asynchrony on their offspring.

异步孵化是小白鹭Egretta garzetta中常见的孵化模式但是，它在维持兄弟姐妹之间的主导关系和进食等级方面的作用仍然研究不足。在这项研究中，我们使用有关突尼斯南部繁殖地小白鹭雏鸟的进食和侵略行为的数据调查了这个问题。我们发现，高级雏鸟是最早获取其父母带来的食物的人，他们摄入的食物比年轻的兄弟姐妹要多。中级雏鸟最经常参与侵略。最年轻的雏鸟表现出更多的低调和少有攻击性的行为，因此比年长的雏鸟少吃些东西，但啄和受伤少得多。这些发现强调了孵化顺序对于在小白鹭兄弟姐妹之间建立饲养层次的重要性。此外，他们认为，获取食物可能不是塑造雏鸟喂养行为和竞争力的独特因素，因为避免因兄弟姐妹的袭击而造成的伤害可能很重要。最后，成年鸟类似乎采取了“放任自由”的策略，没有表现出喂养偏爱来抵消或加强孵化异步对后代的影响。