Flight behaviour of seabirds in relation to wind direction and wing morphology

We studied flight direction relative to wind direction (hereafter referred to as "flight direction"), the relation between wing morphology and flight behaviour and interspecies relationships in flight behaviour among all major seabird taxa. We calculated wing loading and aspect ratios for 98 species from 1029 specimens. Species were sorted into 13 groups on the basis of similarity in patterns of flight direction. The primary flight direction of Pelecaniformes and Charadriiformes was into and across headwinds. The most common flight direction of Procellariiformes was across wind. Seabirds avoided flying with tailwinds. Wing loading and aspect ratios were positively correlated in Procellariiformes, Pelecaniformes and alcids but negatively correlated in larids. In Procellariiformes, incidence of headwind flight and that of tailwind flight were significantly correlated with wing loading and aspect ratio; species with higher wing loading and aspect ratios flew more often into headwinds and less often with tailwinds. In contrast, the proportion of Pelecaniformes and Charadriiformes flying with tailwinds increased significantly with increased wing loading. Our results demonstrate a close link in seabirds between flight behaviour, wing morphology and natural history patterns in terms of distribution, colony location, dispersal and foraging behaviour.