Hatching asynchrony in birds occurs when incubation commences prior to clutch completion and results in broods containing different aged and sized nestlings. The brood reduction hypothesis predicts that hatching asynchrony is a strategy that facilitates the partial success of brood, as feeding to old and large nestlings which results in adaptive brood reduction under periods of food shortage. Using stochastic simulation, we tested and specified the outcome of the brood reduction hypothesis with various provisioning variables of birds to investigate under what conditions the brood reduction effectively explains the evolution of hatching asynchrony. Asynchronous hatching can be productive as provisioning by parents is preferentially feeding to old nestlings when food is not sufficiently available, while it did not create substantial differences in the number of nestlings fledged when food was equally allocated to all nestlings. Secondly, in the case where food items are large and fewer deliveries are needed, asynchronous hatching becomes more favoured compared to smaller, more frequently delivered, food items. Also, when parents provision less food than was needed on bad days, hatching asynchrony became favoured even when the bad days occur infrequently. Different life traits of each bird can change the expectation of the brood reduction hypothesis.

中文翻译：

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在什么条件下减少育雏有效？

当孵化在离合器完成之前开始时会发生鸟类的孵化不同步，并导致包含不同年龄和大小的雏鸟的育雏。育雏减少假说预测孵化异步是一种促进育雏部分成功的策略，因为喂食老而大的雏鸟，这会导致在食物短缺时期适应性减少育雏。使用随机模拟，我们使用各种鸟类供应变量测试并指定了育雏减少假设的结果，以研究在什么条件下育雏减少有效地解释了孵化异步的演变。异步孵化可以提高生产力，因为当食物不足时，父母会优先喂养老雏鸟，虽然当食物平均分配给所有雏鸟时，它并没有在羽化雏鸟数量上产生实质性差异。其次，在食品较大且需要较少交付的情况下，与较小、更频繁交付的食品相比，异步孵化变得更受欢迎。此外，当父母提供的食物少于糟糕的日子所需的食物时，即使糟糕的日子很少发生，孵化异步也会受到青睐。每只鸟的不同生活特征会改变育雏假设的预期。当父母提供的食物少于糟糕的日子所需的食物时，即使糟糕的日子很少发生，孵化异步也会受到青睐。每只鸟的不同生活特征会改变育雏假设的预期。当父母提供的食物少于糟糕的日子所需的食物时，即使糟糕的日子很少发生，孵化异步也会受到青睐。每只鸟的不同生活特征会改变育雏假设的预期。