2 research outputs found
Links between fear of humans, stress and survival support a non-random distribution of birds among urban and rural habitats
Urban endocrine ecology aims to understand how organisms cope with new sources of stress
and maintain allostatic load to thrive in an increasingly urbanized world. Recent research efforts
have yielded controversial results based on short-term measures of stress, without exploring its
fitness effects. We measured feather corticosterone (CORTf, reflecting the duration and amplitude
of glucocorticoid secretion over several weeks) and subsequent annual survival in urban and rural
burrowing owls. This species shows high individual consistency in fear of humans (i.e., flight initiation
distance, FID), allowing us to hypothesize that individuals distribute among habitats according to
their tolerance to human disturbance. FIDs were shorter in urban than in rural birds, but CORTf
levels did not differ, nor were correlated to FIDs. Survival was twice as high in urban as in rural birds
and links with CORTf varied between habitats: while a quadratic relationship supports stabilizing
selection in urban birds, high predation rates may have masked CORTf-survival relationship in rural
ones. These results evidence that urban life does not constitute an additional source of stress for
urban individuals, as shown by their near identical CORTf values compared with rural conspecifics
supporting the non-random distribution of individuals among habitats according to their behavioural
phenotypesPeer reviewe