Serrano, D., Cortés-Avizanda, A., Zuberogoitia, I., Blanco, G. et al. 2021. Phenotypic and environmental correlates of natal dispersal in a long-lived territorial vulture. Scientific Reports 11, 5424, doi:10.1038/s41598-021-84811-8
Abstract: Natal dispersal, the movement between the birth and the first breeding
site, has been rarely studied in long-lived territorial birds with a
long-lasting pre-breeding stage. Here we benefited from the long-term
monitoring programs of six populations of Egyptian vultures (Neophron percnopterus)
from Spain and France to study how the rearing environment determines
dispersal. For 124 vultures, we recorded a median dispersal distance of
48 km (range 0–656 km). Linear models were used to assess the effect of
population and individual traits on dispersal distance at two spatial
scales. Dispersal distances were inversely related to vulture density in
the natal population, suggesting that birds perceive the abundance of
conspecifics as a signal of habitat quality.
This was particularly true
for declining populations, so increasing levels of opportunistic
philopatry seemed to arise in high density contexts as a consequence of
vacancies created by human-induced adult mortality. Females dispersed
further than males, but males were more sensitive to the social
environment, indicating different dispersal tactics. Both sexes were
affected by different individual attributes simultaneously and
interactively with this social context. These results highlight that
complex phenotype-by-environment interactions should be considered for
advancing our understanding of dispersal dynamics in long-lived
organisms.
