Life history traits, bioclimate, and migratory systems of raptors

What is it about?

Although migration is a widespread phenomenon across a range of taxa, the evolution of migratory behaviour remains insufficiently understood. Therefore, the aim of this study was to examine the relationships between migratory behaviour and life history traits of diurnal birds of prey (Accipitriformes) in a phylogenetic context and also to investigate the bioclimatic suitability of geographical ranges for migratory raptors. We performed phylogenetic generalized least square analysis, using a previously published phylogenetic tree of 179 accipitrid raptors, to identify relationships among distribution patterns, diet, hunting strategies, body measurements, clutch size, and migratory behaviour. Bioclimatic data were employed into computer learning maximum entropy modelling (Maxent) to specify differences between climatic conditions on breeding and wintering grounds. Clutch size and hunting strategies have been proved to be the most important variables in shaping distribution areas, and also the geographic dissimilarities may mask important relationships between life history traits and migratory behaviours. However, this result supports the need for distinctions among the three major migratory routes in raptors. Indeed, the West Palearctic-Afrotropical and the North-South American migratory systems are fundamentally different from the East Palearctic-Indomalayan system, owing to the presence versus absence of ecological barriers. This suggests that the migratory behaviours differ among the three main migratory routes for these species. Future studies could uncover the causes of differences among the three main flyways in more detail.

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