Arctic ecosystems are changing rapidly. The tundra supports nesting migratory seabirds that spend most of their year over the ocean. Migrations are demanding, but it is unclear how physiological capability may equip organisms to respond to their changing environments. For two migratory seabird species nesting in Alaska, USA, the Arctic tern (n = 10) and the long-tailed jaeger (n = 8), we compared oxidative physiology and aerobic capacity measured during incubation and we recorded individual movement paths using electronic tracking tags. Within species, we hypothesized that individuals with longer-distance migrations would show higher oxidative stress and display better aerobic capacity than shorter-distance migrants. We examined blood parameters relative to subsequent fall migration in jaegers and relative to previous spring migration in terns. We present the first measurements of oxidative stress in these species and the first migratory movements of long-tailed jaegers in the Pacific Ocean. Arctic terns displayed positive correlation of oxidative variables, or better integration than jaegers. Relative to physiological sampling, pre-breeding northward migration data were available for terns and post-breeding southward data were available for jaegers. Terns reached a farther maximum distance from the colony than jaegers (16 199 ± 275 km versus 10 947 ± 950 km) and rate of travel northward (447 ± 41.8 km/day) was positively correlated with hematocrit, but we found no other relationships. In jaegers, there were no relationships between individuals’ physiology and southward rate of travel (193 ± 52.3 km/day) or migratory distance. While it is not clear whether the much longer migrations of the terns is related to their better integration, or to another factor, our results spark hypotheses that could be evaluated through a controlled phylogenetic study. Species with better integration may be less susceptible to environmental factors that increase oxidative stress, including thermal challenges or changes in prey distribution as the Arctic climate changes rapidly.

中文翻译：

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两种小型且高度洄游的北极海鸟的氧化生理学：北极燕鸥 (Sterna paradisaea) 和长尾捕鸟 (Stercoarius longicaudus)

北极生态系统正在迅速变化。苔原为筑巢的迁徙海鸟提供了栖息地，这些海鸟一年中的大部分时间都在海洋上度过。迁徙的要求很高，但尚不清楚生理能力如何使生物体能够应对不断变化的环境。对于在美国阿拉斯加筑巢的两种迁徙海鸟——北极燕鸥（n = 10）和长尾猎鸟（n = 8），我们比较了孵化期间测量的氧化生理和有氧能力，并使用电子跟踪记录了个体的运动路径标签。在物种内部，我们假设长途迁徙的个体会比短距离迁徙的个体表现出更高的氧化应激并表现出更好的有氧能力。我们检查了与野鸟随后秋季迁徙相关的血液参数以及与燕鸥先前春季迁徙相关的血液参数。我们首次测量了这些物种的氧化应激，并首次测量了长尾猎豹在太平洋的首次迁徙活动。北极燕鸥表现出氧化变量的正相关性，或者比猎鹰更好的整合。相对于生理采样，燕鸥可以得到繁殖前向北迁徙的数据，而野鸟可以得到繁殖后向南的数据。燕鸥到达的最大距离比猎鹰更远（16 199 ± 275 公里与 10 947 ± 950 公里），向北旅行的速度（447 ± 41.8 公里/天）与血细胞比容呈正相关，但我们没有发现其他关系。在耶格尔中，个体的生理机能与向南旅行的速度（193±52.3公里/天）或迁徙距离之间没有关系。虽然尚不清楚燕鸥更长的迁徙是否与它们更好的融合有关，还是与其他因素有关，但我们的结果引发了可以通过受控系统发育研究来评估的假设。具有更好整合能力的物种可能不太容易受到增加氧化应激的环境因素的影响，包括随着北极气候迅速变化而带来的热挑战或猎物分布的变化。