WING DESIGN AND MIGRATORY FLIGHT

Since birds are adapted to occupy different niches and have different migrating strategies, they use different flight modes associated with particular wing designs. Long-distance migrants should have narrow win gs, that is, a high aspect ratio (wingspan(2)/wing area) for flight en durance, short wings for time minimization, and a high wing loading (w eight/wing area) for fast flight. For energy-minimization, long-distan ce migrants should have long wings and a low wing loading. Fast-flying species should have pointed wing tips to reduce profile power and str eamlined bodies to reduce parasite power, whereas rounded wing tips en hance soaring and gliding performance in slow fliers. Mean aspect rati o for 28 long-distance migrating birds is 8.2, whereas short-distance migrants have a lower aspect ratio (mean 7.4, n = 50). The variation i n relative wing loading (body mass(2/3)/wing area) is rather high in b oth groups, but, in general, relative wing loading is lower in long-di stance migrants (mean 5.5) than in short-distance migrants (mean 7.3). The flight of short-distance migrants is predicted to be more expensi ve on average than that in long-distance migrants, which may need more stopovers to feed during their migration flights than species with hi gher aspect ratios. Mean aspect ratio and relative wing loading for 51 sedentary birds are 5.5 and 6.1, respectively, indicating expensive f light.