Natal dispersal—the movement from birthplace to breeding location—is often considered the most significant dispersal event in an animal’s lifetime. Natal dispersal distances may be shaped by a variety of intrinsic and extrinsic factors, and remain poorly quantified in most groups, highlighting the need for indices that capture variation in dispersal among species.

In birds, it is hypothesized that dispersal distance can be predicted by flight efficiency, which can be estimated using wing morphology. However, the use of morphological indices to predict dispersal remains contentious and the mechanistic links between flight efficiency and natal dispersal are unclear.

Here, we use phylogenetic comparative models to test whether hand-wing index (HWI, a morphological proxy for wing aspect ratio) predicts natal dispersal distance across a global sample of 114 bird species. In addition, we assess whether HWI is correlated with flight usage in foraging and daily routines.

We find that HWI is a strong predictor of both natal dispersal distance and a more aerial lifestyle.

Our results support the use of HWI as a valid proxy for relative natal dispersal distance, and also suggest that evolutionary adaptation to aerial lifestyles is a major factor connecting flight efficiency with patterns of natal dispersal.

These data include: 

1) A dataset of natal dispersal distances (km) for 114 species of birds. For each species, diet classification, migratory strategy, habitat preference, aerial lifestyl index, and hand-wing index data are provided. For details on each variable, see Weeks et al. 2022. Morphological adaptations linked to flight efficiency and aerial lifestyle determine natal dispersal distance in birds. Functional Ecology.

2) A 50% majority rule consensus phylogeny, derived from birdtree.org, as outlined in Weeks et al. 2022. Morphological adaptations linked to flight efficiency and aerial lifestyle determine natal dispersal distance in birds. Functional Ecology.

3) An R script to replicate all analyses performed using these data, reported in Weeks et al. 2022. Morphological adaptations linked to flight efficiency and aerial lifestyle determine natal dispersal distance in birds. Functional Ecology.