Mixed‐species colonies occur frequently, especially among seabirds, and may provide mutual benefits among associated species including antipredator advantages. The “protector” species in such associations may provide early warning signals or by aggressively defending their own nests, may expel predators from the area. We explored costs and benefits to Rockhopper Penguins (Eudyptes chrysocome) in relation to offspring production in both monospecific colonies and those mixed with Imperial Cormorants (Phalacrocorax atriceps) at Saunders Island (Falkland Islands), emphasizing differences in predation pressure. We considered behavioral responses of chicks (in crèches), as well as differences in their nutritional condition, morphometric measurements, and survival compared among different breeding colonies. Our study revealed a paradox: High‐quality adult penguins, those arriving early and occupying lower‐elevation sites closer to the coast, produced better‐nourished chicks earlier in the season. However, they averaged half the number of chicks fledged, compared to breeders that arrived later in the season. Late breeders were forced by unavailability of optimal habitat to nest in more elevated areas, forming mixed colonies with cormorants, which, in turn, provided them with protection from nest predators. This study provides an example of the role of luck in nature, and how it may compensate for differences in individual fitness.

中文翻译：

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福克兰群岛的凤冠企鹅–帝王mixed混合殖民地：对后期繁殖者来说是好运

混合物种殖民地经常发生，特别是在海鸟中，并且可能在相关物种之间提供互利，包括反捕食者的优势。这种协会中的“保护者”物种可能会发出预警信号，或者通过积极捍卫自己的巢穴，可能将掠食者赶出该地区。我们探讨了成本和收益，以跳岩企鹅（Eudyptes chrysocome相对于两个单特异性克隆后代的生产和那些与帝国鸬鹚混合）（鸬鹚atriceps）在桑德斯岛（福克兰群岛），强调捕食压力的差异。我们考虑了雏鸡的行为反应（在托儿所中），以及它们的营养状况，形态测量值和存活率在不同繁殖群体之间的差异。我们的研究揭示了一个悖论：优质成年企鹅，它们较早到达，并在靠近海岸的地方海拔较低的地方，在该季节的早期产生了营养更好的雏鸡。但是，相比于本赛季晚些时候抵达的种鸡，它们平均出雏幼鸡的数量减少了一半。由于无法获得最佳栖息地，后期育种者不得不在更高的地区筑巢，与with形成混合菌落，从而为它们提供了免受巢穴掠食者的保护的机会。这项研究提供了一个例子，说明运气在自然界中的作用，