The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two flyways from the measured isotope values of migrant's feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins then those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.

中文翻译：

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使用氧和氢稳定同位素追踪锋利的鹰类（Accipiter striatus）沿北美西部航道的迁移运动

在北美洲西部发现的小森林鹰“尖刀鹰”（Accipiter striatus）的大规模活动模式是未知的。但是，根据实地观察，我们着手检验少年移栖曲霉的假说沿北美内华达山脉对岸的两条截然不同的迁移路线（太平洋海岸和山间迁徙飞越）捕获的来自不同地理背景的出生人口。我们应用了羽毛中氢（H）和氧（O）的稳定同位素分析，以及空间同位素变化（isoscapes）的大规模模型来制定迁徙鸟类起源的空间明确预测。新的关系进行了评估之间的氢和氧同位素值的羽毛从A. striatus的关系已知来源的博物馆标本，以及在那些已知位置进行的等值线模拟降水的氢和氧同位素值。我们使用这些关系从被测者的羽毛的同位素值以及形成这些羽毛的相关氢，氧同位素组成的降水量中，预测了沿着两个飞行路线迁移的鸟类的起源区域。来自这两种迁徙路线的鸟的出生/繁殖起源重叠，并且没有分化成完全独立的迁徙种群，太平洋沿岸迁徙飞行道的鸟类比山间迁徙的鸟类具有更广泛的出生地理起源。通常，基于氧同位素的方法比基于氢的方法具有较小的预测能力。两种同位素方法在沿太平洋海岸迁徙路线迁徙的鸟类的地理分配中已达成广泛共识，但对于沿山间迁徙迁徙路线迁徙的鸟类则没有广泛的共识。讨论了这些结果对保护区工作的意义。北美西部的纹状体，以及使用氢和氧稳定同位素组合分析来跟踪大陆规模上猛禽的运动。