The timing of events in the early part of the breeding season is crucially important for successful reproduction. Long-lived animals that migrate large distances independently of each other meet at the breeding sites to re-establish their pair bonds and coordinate their breeding duties with their partners. Using miniature light-geolocation and immersion data together with blood stable isotopes, we studied the early breeding season in Thin-billed prions Pachyptila belcheri, Antarctic prions P. desolata and Blue petrels Halobaena caerulea breeding at Kerguelen Islands in the Indian Ocean. These three species exhibit differences in their winter habitat and timing of migration, moult and breeding. We hypothesised that these differences would influence their behaviour during the early breeding season. In line with our hypothesis, we found clear differences not only in the timing of colony attendance, but also in the time budgets while at sea and in habitat use. Both early breeding Blue petrels and late breeding Antarctic prions spent about 8 h per day in flight and 15 h foraging. In comparison, Thin-billed prions, which breed in mid-summer, spent less time (5 h daily) in flight and more time (18 h daily) foraging, thus maximizing the time spent foraging during the longest daylight days of the year. While the ecological habitat parameters (sea temperature, wind, productivity) of Thin-billed prions and Blue petrels were relatively stable throughout the year, Antarctic prions showed clear niche switching, caused by leapfrogging between the northernmost winter distribution to the southernmost distribution during the early breeding season. Blood stable isotopes confirmed the habitat switch between the inter-breeding and early breeding periods and highlighted trophic segregation with Blue petrels feeding more on fish and Antarctic petrels more on crustaceans during the early breeding period. We found that the three sympatric petrel species segregated in time and space, both in the winter and the early breeding season. The interplay of timing and distribution meant that the three species show the full range of migratory strategies, from niche-tracking Blue petrels to niche-switching Antarctic prions. The latitudinal distribution resembled the leapfrogging of terrestrial avian migrant species or populations.

中文翻译：

---

生态位转换和越级觅食：同域海燕早期繁殖季节的运动生态学。

繁殖季节早期的事件发生时间对于成功繁殖至关重要。彼此独立迁徙远距离的长寿动物在繁殖地相遇，以重新建立它们的配对关系，并与它们的伙伴协调它们的繁殖职责。利用微型光地理定位和浸没数据以及血液稳定同位素，我们研究了印度洋 Kerguelen 群岛薄嘴朊病毒 Pachyptila belcheri、南极朊病毒 P. desolata 和蓝海燕 Halobaena caerulea 的早期繁殖季节。这三个物种在冬季栖息地和迁徙、换羽和繁殖时间方面表现出差异。我们假设这些差异会影响它们在早期繁殖季节的行为。与我们的假设一致，我们发现，不仅在殖民地出现的时间上存在明显差异，而且在海上和栖息地使用的时间预算上也存在明显差异。早期繁殖的蓝海燕和晚期繁殖的南极朊病毒每天都花费大约 8 小时的飞行时间和 15 小时的觅食时间。相比之下，在仲夏繁殖的薄嘴朊病毒在飞行中花费的时间更少（每天 5 小时），而觅食的时间更长（每天 18 小时），从而最大限度地延长了一年中最长白天的觅食时间。虽然薄嘴朊病毒和蓝海燕的生态栖息地参数（海水温度、风、生产力）全年都相对稳定，但南极朊病毒表现出明显的生态位转换，这是由于早期冬季分布最北端向最南端分布的跨越造成的。繁殖季节。血液稳定同位素证实了杂交和早期繁殖期之间的栖息地转换，并强调了营养隔离，在早期繁殖期，蓝海燕更多地以鱼类为食，而南极海燕更多地以甲壳类动物为食。我们发现，在冬季和早期繁殖季节，三种同域海燕物种在时间和空间上都是隔离的。时间和分布的相互作用意味着这三个物种展示了全方位的迁徙策略，从生态位追踪蓝海燕到生态位转换的南极朊病毒。纬度分布类似于陆地鸟类迁徙物种或种群的跨越式。