ABSTRACT: Ecologically similar species partition their use of resources and habitats and thus coexist due to ecological segregation in space, time, or diet. In seabirds, this segregation may differ over the annual cycle or vary inter-annually. We evaluated niche segregation in 3 sympatric storm-petrel species (Hydrobates melania, H. leucorhous, and H. microsoma) from the San Benito Islands, Mexico, during 2012 and 2013. We used diet samples and carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopic values obtained from egg membranes, blood, feathers, and prey. We used krill samples to delineate marine δ¹³C and δ¹⁵N isoscapes for the Baja California Peninsula. During the breeding season, storm-petrels segregated regarding diet composition, stable isotope values, and isotopic niches. H. melania consumed higher trophic-position prey from neritic waters, while H. leucorhous and H. microsoma foraged on lower-trophic position prey from oceanic waters. Isotopic niches among species did not overlap in 2013, whereas those of H. microsoma and H. leucorhous overlapped in 2012. The feeding strategies of H. melania varied among breeding phases, and adults consumed different prey items from different areas compared to those of their offspring. H. microsoma adults and their chicks consumed the same prey items but from different habitats. During the non-breeding period, niche segregation between species persisted, except for H. microsoma and H. leucorhous during the molt of primary (P1) and undertail cover feathers. These 3 sympatric species coexist through niche segregation based on prey items and foraging areas that vary seasonally and year-round, probably due to changes in oceanographic conditions and the distribution and availability of prey.

中文翻译：

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来自下加利福尼亚州半岛，墨西哥，东太平洋的三个同胞Hydrobates风暴海燕的全年利基分离

摘要：生态上相似的物种划分了资源和栖息地的使用范围，因此由于空间，时间或饮食上的生态隔离而共存。在海鸟中，这种隔离可能在一年周期中有所不同，或者每年不同。我们评估利基偏析在3同域风暴海燕物种（Hydrobates梅拉，H. leucorhous，和H. microsoma 2012年和2013年，我们使用饮食样品和碳（δ期间从圣贝尼托群岛，墨西哥，）¹³ C）和氮（δ ¹⁵ N）从蛋膜，血，羽毛和猎物获得同位素值。我们用磷虾样品划定海洋δ ¹³ C和δ ¹⁵下加利福尼亚半岛的N个等值线。在繁殖季节，风暴海燕因日粮组成，稳定的同位素值和同位素生态位而隔离。H. melania消耗了来自营养水的较高营养位置的猎物，而H. leucorhous和H. microsoma则从海洋水的低营养位置的猎物中觅食。物种之间的同位素龛没有重叠在2013年，而那些H. microsoma和H. leucorhous在2012年重叠的喂养策略H.梅拉繁殖阶段各不相同，和成年人相比，那些消耗来自不同地区不同的猎物他们后代。微小体成年和它们的小鸡消耗相同的猎物，但来自不同的栖息地。在非繁殖期间，物种之间小生偏析持续，除了H. microsoma和H. leucorhous初级（P1）的蜕皮期间和undertail盖羽毛。这三种同胞物种通过基于猎物的生态位隔离和季节性和全年变化的觅食区域共存，这可能是由于海洋条件的变化以及猎物的分布和可利用性造成的。