在山區範圍內，短距離遷徙的鳥類主要受食物來源穩定性的影響，而非氣候因素。一項針對喜馬拉雅地區鳥類族群與昆蟲數量的最新研究發現，以捕食地面或空中昆蟲為食的鳥類會在冬季因食物減少而向低海拔遷移；相比之下，以葉食性昆蟲為食的鳥類往往全年留在相同海拔，因為這類昆蟲仍保持一定數量。

Short-distance migrations within mountain ranges are primarily driven by the stability of food sources rather than by climate. A recent study that tracked bird populations and insect numbers in the Himalayas found that birds that feed on ground-dwelling or airborne insects move to lower elevations in winter when their food becomes scarce. By contrast, birds that feed on leaf-eating insects tend to remain at the same elevation year-round because those insects remain available.

https://www.earth.com/news/some-birds-move-through-mountains-for-a-reason-scientists-are-now-seeing/