Limited sexual segregation in a dimorphic avian scavenger, the Andean condor

PERRIG, PAULA L.; LAMBERTUCCI SERGIO; PABLO A.E. ALARCÓN; ARTHUR D.MIDDLETON; PADRÓ JULIAN; PABLO I.PLAZA; BLANCO, GUILLERMO; SÁNCHEZ-ZAPATA JOSÉ; DONÁZAR JOSÉ ANTONIO; JONATHAN N. PAULI

OECOLOGIA

SPRINGER

Lugar: Berlin; Año: 2021

0029-8549

Sexual segregation is widely reported among sexually dimorphic species and generally attributed to intraspecific competition. Prey diversity and human activities can reinforce niche segregation by increasing resource heterogeneity. Here, we explored trophic and spatial sexual segregation in the only avian scavenger that exhibits pronounced sexual-size dimorphism (up to 50% difference in body mass) and a highly despotic social system, the Andean condor (Vultur gryphus). We predicted that larger and dominant males would exclude smaller and subordinate females from high quality resources, leading to sexual segregation particularly in human-dominated landscapes showing increased prey diversity. We compared resource use between females and males across six sites in Argentina featuring a range of prey diversity via stable isotopes analysis of molted feathers (n = 141 individuals). We then focused on two sites featuring contrasting levels of prey diversity and quantified assimilated diet via stable isotopes and space use via GPS monitoring (n = 23 13 and 12 tagged individuals). We found no clear differences in isotopic niche space, 14 individual variation in isotopic signature, or assimilated diet between females and males. 15 However, there were differences in foraging locations between sexes, with females 16 apparently using areas of fewer food resources more frequently than males. Local 17 conditions defined the dynamics of fine-scale sexual differences in foraging sites; yet, 18 unpredictable and ephemeral carrion resources likely prevent segregation by sexes at the 19 landscape scale. Our study highlights complex dynamics of sexual segregation in vultures 20 and the relevancy of analyses under multiple spatial-temporal scales to explore segregation 21 in social species.