Habitat selection is expected to balance benefits and costs that maximizes fitness. Using a rare data set on collared lemming (Dicrostonyx groenlandicus) winter nest location spanning more than two decades, we show that lemmings actively select for Salix snow beds, likely due to its favorable micro-climate, and that lemming habitat selection was density-dependent. Lemmings nevertheless exhibited some flexibility in their habitat selection, which appeared to be influenced by the year-to-year variation in snow conditions. The likelihood of both lemming breeding and nest predation by stoats (Mustela erminea) was not directly linked to habitat despite a delicate interplay between habitat, nest size, breeding, and predation. Hence, the larger lemming nests were found in Salix snow beds, and these were more often used for breeding, but both larger nests and nests used for breeding were also predated more often than other nests. Our study provides a clear example of how density-dependent habitat selection acts to balance fitness in the various habitats utilized by collared lemmings.

栖息地的选择有望在收益和成本之间取得平衡，从而使适应性最大化。使用跨越20年以上的颈圈旅鼠（Dicrostonyx groenlandicus）冬季巢穴位置的罕见数据集，我们表明旅鼠积极选择柳柳雪床，可能是由于其有利的微气候，旅鼠栖息地的选择取决于密度。尽管如此，在生活环境的选择上，它们仍表现出一定的灵活性，这似乎受到雪况逐年变化的影响。旅鼠繁殖和巢捕食的可能性（鼬鼬）尽管栖息地，巢大小，繁殖和捕食之间存在微妙的相互作用，但它与栖息地没有直接联系。因此，在柳属雪床中发现了更大的旅巢，这些巢通常被用于繁殖，但是大型巢和用于繁殖的巢也比其他巢更被捕食。我们的研究提供了一个清晰的例子，说明依赖密度的栖息地选择如何发挥作用，平衡衣领旅鼠在各种栖息地中的适应度。