Contrasting use and selection of natural fissures between Andean Swift (Aeronautes andecolus) and White-collared Swift (Streptoprocne zonaris) in mountains of Central Argentina

Abstract

Coexisting and similar species will often partition the available habitat. We tested the hypothesis that coexisting Andean (Aeronautes andecolus) and White-collared Swifts (Streptoprocne zonaris) select different fissure morphologies when selecting roosting or nesting sites. A total of 184 fissures were characterised. Principal Coordinates Analysis showed that the characteristics of the fissures differed between the species, height of the wall and the distance to water are the most explanatory variables. General linear mixed models showed that for Andean Swifts, the selection of fissures was influenced by the height of the wall, the relative position of the fissure in it, and the width of the entrance. For White-collared Swift, the selection was influenced by the distance to water and the distance to nearest vegetation. Our results suggest niche partitioning between the two swift species and that coexistence of these species is explained by contrasting habitat use and selection.