Migration is an energetically expensive activity with important links to population dynamics of migratory birds. Identification of high-quality stopover habitat to support migratory refueling is, therefore, important for woodland migrant conservation. Woodland habitat is scarce in the northern prairie region, consisting of natural riparian corridor woodlands (corridors) and anthropogenic woodlots (woodlots), but supports large numbers of migrant birds during stopover. To assess prey abundance, diet composition, and effects of prey abundance on the energetic condition of insectivorous migrant landbirds at corridors and woodlots in the northern prairie region, we sampled arthropods from the two habitats and collected fecal samples to ascertain migrant bird diets during spring and fall migrations. We found that standardized arthropod counts and biomass from all sampling methods showed no consistent differences between corridors and woodlots in either season. Araneae, Coleoptera, Hemiptera, Diptera, and Hymenoptera were the dominant arthropod taxa in both seasons for both habitats. Migrant diets contained large proportions of Coleoptera, Diptera, and Hemiptera in fall and Hymenoptera, Coleoptera, and Diptera in spring at both habitats. Dietary analyses of percentage biomass revealed different patterns, with Lepidoptera highest in both seasons. Annual differences in arthropod counts and biomass were evident for both seasons, with lower counts and biomass in fall 2011 than in fall 2010 and in spring 2011 than in springs of 2010 and 2012. Only arthropods collected by sticky traps were positively correlated with plasma metabolites associated with refueling rates, and habitat type was not a significant predictor of plasma metabolite levels. These data collectively suggest that arthropods were present in sufficient abundance and diversity at both corridors and woodlots for migrant birds to successfully refuel at these riparian stopover sites.

中文翻译：

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节肢动物的猎物和林地迁徙者的饮食在北部草原地区的天然河岸林地和人为林地之间是相似的

迁徙是一项耗能巨大的活动，与候鸟的种群动态有重要联系。因此，确定高质量的中途停留栖息地以支持迁徙加油对于林地迁徙者保护非常重要。北部草原地区的林地栖息地稀少，由天然河岸走廊林地（corridors）和人为林地（woodlots）组成，但在中途停留期间支持大量候鸟。为了评估猎物丰度、饮食组成以及猎物丰度对北部草原地区走廊和林地食虫候鸟精力充沛状况的影响，我们从两个栖息地采集了节肢动物样本，并收集了粪便样本，以确定春季和夏季候鸟的饮食。秋季迁徙。我们发现，来自所有采样方法的标准化节肢动物计数和生物量显示，在任一季节，走廊和林地之间没有一致的差异。蛛形纲、鞘翅目、半翅目、双翅目和膜翅目在两个栖息地的两个季节都是主要的节肢动物类群。在这两个栖息地，迁徙者的饮食在秋季含有大量的鞘翅目、双翅目和半翅目，在春季则含有大量的膜翅目、鞘翅目和双翅目。生物量百分比的饮食分析揭示了不同的模式，鳞翅目在两个季节中最高。节肢动物数量和生物量的年度差异在两个季节都很明显，2011 年秋季的数量和生物量低于 2010 年秋季，2011 年春季低于 2010 年和 2012 年春季。只有粘性陷阱收集的节肢动物与与加油率相关的血浆代谢物呈正相关，栖息地类型不是血浆代谢物水平的重要预测因子。这些数据共同表明，节肢动物在走廊和林地中的数量和多样性都足以让候鸟在这些河岸中途停留点成功补充能量。