Aim To evaluate (1) whether three migratory nightjar species (Family Caprimulgidae) adhere to Bergmann's rule, (2) whether environmental factors on the breeding or wintering grounds determine body size, and (3) which mechanistic hypotheses best explain Bergmannian patterns in body size. Location North and South America; Europe and Africa. Taxon Eastern whip‐poor‐will ( Antrostomus vociferus ), Common nighthawk ( Chordeiles min...

Accelerated biodiversity loss has destabilized functional links within and between ecosystems. Species that cross different ecosystems during migration between breeding and nonbreeding sites are particularly sensitive to global change because they are exposed to various, often ecosystem‐specific, threats. Because these threats have lethal and nonlethal effects on populations, many migratory species are declining, making this g...