Sex differences in short-distance natal dispersal in American Kestrels (Falco sparverius) in Central Argentina

Abstract

Dispersal is the process by which individuals move through different sites away from their natal place during their life. Many factors can regulate dispersal movements of individuals, from intrinsic characteristics of the individuals to environmental conditions. Here, we report American Kestrel (Falco sparverius) natal dispersal in central Argentina and analyse some of the factors that can modulate it. We also report information on breeding dispersal, and nest box fidelity, using banding data from 2011 to 2019. The number of kestrels banded was high, but only 5.59% of birds were recaptured or re-sighted. Part of the American Kestrel population is philopatric, and most kestrels were detected breeding at 1 year of age for the first time (41.38%). Kestrels bred from one (mostly) to 6 years in the same nest box. Natal dispersal ranged from 2 to 36.9 km, and females dispersed longer distances than males. We did not record kestrels dispersing between the different sampling sites, but we recovered two dead dispersing juveniles more than 200 km from their natal nest, suggesting some long-distance dispersal may occur in our studied population. Further banding studies or better, studies based on the tagging of American Kestrels with GPS tracking devices will certainly be needed to better understand dispersal movements and factors that modulate these dispersal patterns in South America.