Dozens of studies have documented that brood parasites are well adapted to a brood parasitic lifestyle but not all parasitism events are successful. Co‐evolution between brood parasites and their hosts is a dynamic process so it is reasonable to expect that a female brood parasite may commit errors during egg deposition by laying her eggs outside the laying period of the host, with consequent impacts on her fitness. Using an extensive dataset from a long‐term study, we evaluated egg‐laying patterns and errors related to the timing of egg‐laying in the Common Cuckoo Cuculus canorus (hereafter ‘Cuckoo’). Specifically, we tested whether the Cuckoo avoids laying before or on the day of host clutch initiation to reduce the risk of rejection of parasitic eggs, whether laying errors will be more frequent in periods with a lack of active host nests, and whether the laying errors will be more frequent in periods with intense Cuckoo parasitism and a consequent lack of suitable host nests. We found that about one‐third of Cuckoo eggs were laid on the host clutch initiation day or 1 day before, and the percentage of Cuckoo eggs laid decreased thereafter. Surprisingly, the probability of Cuckoo egg acceptance by the hosts was not affected by the egg‐laying stage of the host clutch. Errors in the timing of egg‐laying with fatal consequences (i.e. those precluding Cuckoo hatching because of laying in incubated or deserted clutches) were recorded in about 5% of cases. Only laying date of a Cuckoo egg had a significant effect on the probability of errors, which increased during the breeding season. This may be related to the higher number of deserted and incubated host nests at the site at the end of the breeding season. Errors in egg‐laying may be attributed to young and inexperienced females but also impaired body condition or intraspecific competition may cause this behaviour. Future studies, which will test these possible explanations, will help to understand better the mechanism of co‐evolutionary arms races and differences between host specialist and generalist brood parasites in various host–parasite systems.

中文翻译：

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杜鹃母杜鹃在其共同宿主的巢中产卵的错误

数十项研究已证明，亲蝇寄生虫非常适合于寄生虫的生活方式，但并非所有寄生虫事件都能成功。亲鱼寄生虫与其寄主之间的共同进化是一个动态过程，因此可以合理预期雌性寄生虫可能会通过将卵产于寄主的产卵期之外而在产卵过程中犯错，从而影响其健康状况。使用来自长期研究的广泛数据集，我们评估了布谷鸟杜鹃的产卵模式和与产卵时间有关的误差。（以下简称“布谷鸟”）。具体来说，我们测试了杜鹃是否在寄主离合启动前或当天避免产蛋，以减少拒绝寄生卵的风险，在缺乏活动寄主巢的时期是否会更频繁地产蛋，以及产蛋是否错误在强烈的布谷鸟（Cuckoo）寄生虫症和因此缺乏合适的寄主巢的时期，这种病会更加频繁。我们发现，约有三分之一的布谷鸟蛋在寄主抓捕开始的第一天或前一天产下，此后布谷鸟蛋的百分比下降。令人惊讶的是，寄主接受杜鹃蛋的概率不受寄主离合器产卵阶段的影响。产卵时间错误会带来致命后果（即 约有5％的案例记录了那些因放置在孵化器中或被遗弃的离合器而阻止布谷鸟孵化的动物。布谷鸟蛋的产蛋日期对错误概率的影响很大，错误概率在繁殖季节增加。这可能与繁殖季节结束时该地点更多的空巢和孵化的寄主巢有关。产蛋错误可能归因于年轻和缺乏经验的女性，但身体状况不佳或种内竞争也可能导致这种行为。未来的研究将检验这些可能的解释，将有助于更好地理解共同进化军备竞赛的机制以及各种寄主－寄生虫系统中寄主专家和通才亲鱼之间的差异。布谷鸟蛋的产蛋日期对错误概率的影响很大，错误概率在繁殖季节增加。这可能与繁殖季节结束时该地点更多的空巢和孵化的寄主巢有关。产蛋错误可能归因于年轻和缺乏经验的女性，但身体状况不佳或种内竞争也可能导致这种行为。未来的研究将检验这些可能的解释，将有助于更好地理解共同进化军备竞赛的机制以及各种寄主－寄生虫系统中寄主专家和通才亲鱼之间的差异。布谷鸟蛋的产蛋日期对错误概率的影响很大，错误概率在繁殖季节增加。这可能与繁殖季节结束时该地点更多的空巢和孵化的寄主巢有关。产蛋错误可能归因于年轻和缺乏经验的女性，但身体状况不佳或种内竞争也可能导致这种行为。未来的研究将检验这些可能的解释，将有助于更好地理解共同进化军备竞赛的机制以及各种寄主－寄生虫系统中寄主专家和通才亲鱼之间的差异。这可能与繁殖季节结束时该地点更多的空巢和孵化的寄主巢有关。产蛋错误可能归因于年轻和缺乏经验的女性，但身体状况不佳或种内竞争也可能导致这种行为。未来的研究将检验这些可能的解释，将有助于更好地理解共同进化军备竞赛的机制以及各种寄主－寄生虫系统中寄主专家和通才亲鱼之间的差异。这可能与繁殖季节结束时该地点更多的空巢和孵化的寄主巢有关。产蛋错误可能归因于年轻和缺乏经验的女性，但身体状况不佳或种内竞争也可能导致这种行为。未来的研究将检验这些可能的解释，这将有助于更好地理解共同进化军备竞赛的机制以及各种宿主-寄生虫系统中宿主专家和通才亲鱼之间的差异。