The phylogenetic signal of white rump in Accipitriformes

GARCÍA, NATALIA C.; BALZA, ULISES; LOIS, NICOLÁS A.

Congreso; 2022 Annual Meeting of the Raptor Research Foundation and the Florida Ornithological Society; 2022

Plumage coloration is key for visual communication in birds, but its role has not been equitatively studied across avian taxa. As raptors are not particularly colorful, they have been historically less studied. There are several hypotheses proposed for the evolution of conspicuous plumage patches in birds. Here, we focus on the occurrence of white rump patches in raptors, which has never been studied from an evolutionary perspective.Based on the latest phylogeny of raptors produced by Mindell et al. (2018) and the occurrence of white rump patches following Ferguson-Lees & Christie’s (2001) and the Handbook of Birds of the World (2022) accounts, we performed ancestral state reconstructions and phylogenetic logistic regression to assess the phylogeneticn signal of white rump presence and its association to different factors in Accipitriformes. White/pale rump occurs in almost 18% of the Accipitriformes here considered (n= 206 species). The ancestor of all Accipitriformes most likely did not have a white rump (likelihood = 0.68). The presence of a white rumped showed a low phylogenetic signal, with at least 20 independent origins and a few instances of reversion. Yet, white rump was especially prevalent in some taxa such as the harriers (Circus , 81%, n= 16 species) and in the Chanting and Afrotropical goshawk clade (Melierax /Urotriorchis , 100%, n= 5 species). In the harriers, for instance, the white rump is prevalent in males, while females retain their ‘juvenile’/cryptic plumage, probably associated with incubation, as all but one species (C. assimilis , which show less marked sexual dimorphism and lacks white rump) nest on the ground. Therefore, this first assessment could be useful to clearly define groups of interests in which the evolution of white rump could have selective advantages