Abstract Species breeding in urban environments are highly prone to a wide variety of non-natural, human activities, which range from short-term disturbances to the degradation or loss of suitable habitat. The latter in turn may force individuals to relocate to new sites for foraging or breeding, both of which presumably entails fitness costs due the trade-offs of finding and exploring new habitats. Species showing a high level of spatial foraging specialisation or nest site fidelity are expected to be most vulnerable. In this study, we explored the consequences of nest site loss on the reproductive investment of lesser black-backed gulls (Larus fuscus), a site faithful seabird species breeding in an urban environment. We monitored a population of 1.173 colour-ringed gulls across 13 years, that involved several episodes of spatially restricted loss of breeding habitat. We found that birds which lost their breeding territories reduced their investment into the eggs as reflected in a decrease of the clutch volume. They relocated over larger distances compared to birds that relocated voluntarily. Moreover, the likelihood of skipping the subsequent breeding season increased after a forced relocation. These negative effects of forced relocation likely contribute to the decline in the number of breeding pairs in our urban population as observed during the last ten years, and highlights the importance of maintaining a stable breeding environment in urban areas for the conservation of this and potentially other colonial breeding seabird species.

中文翻译：

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强制巢址搬迁对殖民地海鸟物种的生殖投资产生负面影响

摘要 城市环境中的物种繁殖极易受到各种非自然人类活动的影响，范围从短期干扰到适宜栖息地的退化或丧失。后者反过来可能会迫使个体搬迁到新的地点进行觅食或繁殖，由于寻找和探索新栖息地的权衡，这两者都可能需要健康成本。表现出高度空间觅食专业化或巢址保真度的物种预计最脆弱。在这项研究中，我们探讨了巢址丧失对小黑背海鸥 (Larus fuscus) 繁殖投资的影响，这是一种在城市环境中繁殖的忠实海鸟物种。我们在 13 年内监测了 1.173 只色环海鸥的种群，这涉及数次空间受限的繁殖栖息地丧失。我们发现失去繁殖地的鸟类减少了对鸡蛋的投资，这反映在离合器数量的减少上。与自愿搬迁的鸟类相比，它们搬迁的距离更远。此外，在被迫搬迁后，跳过随后的繁殖季节的可能性增加了。正如过去十年观察到的那样，强制搬迁的这些负面影响可能导致我们城市人口中繁殖对数量的下降，并强调了在城市地区维持稳定繁殖环境以保护这一点和其他潜在的繁殖环境的重要性。殖民地繁殖海鸟物种。我们发现失去繁殖地的鸟类减少了对鸡蛋的投资，这反映在离合器数量的减少上。与自愿搬迁的鸟类相比，它们搬迁的距离更远。此外，在被迫搬迁后，跳过随后的繁殖季节的可能性增加了。正如过去十年观察到的那样，强制搬迁的这些负面影响可能导致我们城市人口中繁殖对数量的下降，并强调了在城市地区维持稳定繁殖环境以保护这一点和其他潜在的繁殖环境的重要性。殖民地繁殖海鸟物种。我们发现失去繁殖地的鸟类减少了对鸡蛋的投资，这反映在离合器数量的减少上。与自愿搬迁的鸟类相比，它们搬迁的距离更远。此外，在被迫搬迁后，跳过随后的繁殖季节的可能性增加了。正如过去十年观察到的那样，强制搬迁的这些负面影响可能导致我们城市人口中繁殖对数量的下降，并强调了在城市地区维持稳定繁殖环境以保护这一点和其他潜在的繁殖环境的重要性。殖民地繁殖海鸟物种。被迫搬迁后，跳过随后的繁殖季节的可能性增加了。正如过去十年观察到的那样，强制搬迁的这些负面影响可能导致我们城市人口中繁殖对数量的下降，并强调了在城市地区维持稳定繁殖环境以保护这一点和其他潜在的繁殖环境的重要性。殖民地繁殖海鸟物种。被迫搬迁后，跳过随后的繁殖季节的可能性增加了。正如过去十年观察到的那样，强制搬迁的这些负面影响可能导致我们城市人口中繁殖对数量的下降，并强调了在城市地区维持稳定繁殖环境以保护这一点和其他潜在的繁殖环境的重要性。殖民地繁殖海鸟物种。