Effects of sex-associated competitive asymmetries on foraging group structure and despotic distribution in Andean condors

摘要: Phenotype-limited interference models assume competitive asymmetries among conspecifics and unequal sharing of resources. Their main prediction is a correlation between dominance status patch quality: dominant individuals should preferentially exploit better-quality habitats. We tested assumptions predictions the phenotype-limited model in Andean condors (Vultur gryphus), New World vulture with strong sexual size dimorphism (males are 30–40% heavier than females). recorded searching birds habitats differing mountains plains. also observed scavenging behaviour at 20 sheep carcasses, videotaped 5 them. Intraspecific hierarchy carcasses was based on size: males dominated females and, within each sex, older younger ones. Adult juvenile occupied extreme positions feeding hierarchy. Aggression directed those belonging to lower hierarchical levels. In high-quality areas (mountains), more arrived carcasses. Juvenile were often low-quality (plains), far from breeding roost sites. GLM analyses individual showed that did not influence time arrival, but low-ranking spent especially if number arrival high. Additionally, less when higher levels present. On other hand, present had positive effect rates individuals, probably because reduction vigilance. These results support most distribution model, although spatial truncated phenotypes observed. Asymmetric pay-off, parental roles selection constraints could favour divergence body condors.