Speed of bird migratory movements as an adaptive behavior

Abstract

The migration speed of 115 bird species from 35 families of 14 orders has been analyzed on the basis of ring recovery data from published sources. The results show that the average speed varies between 10 and 880 km/day and the maximum speed varies between 30 and 1392 km/day, but the respective values in the majority of species fall within the ranges of 20–100 and 40–360 km/day. There is a significant positive correlation between the average and maximum speed values. The ratio between them varies significantly between the species, with the overall average ratio being 4: 1. On average, shorebirds migrate twice as rapidly as passerines, and the average migration speed in birds of prey is slightly higher than in shorebirds. Species of the family Turdidae migrate significantly faster than species of the family Fringillidae, and the latter migrate faster than the Paridae. No significant differences in migration speed have been revealed between the Sylviidae and Turdidae as well as between the Sylviidae and Motacillidae species. The average migration speed in shorebirds shows a significant negative correlation with body mass, but no such correlation is observed in the passerines. In many species, adult birds migrate significantly faster than juveniles, while male and female birds do not differ in this parameter. The average migration speed of passerines is significantly higher among long-distance early-departing nocturnal migrants than in short-distance late-departing diurnal migrants. In some species, the spring migration speed is much higher than the autumn speed. The behavior of migrants in flight and at stopovers is governed by complex interactions between their species-specific foraging habits, weather parameters, and habitat conditions.