Does predation drive Chilean Elaenia (Eleania chilensis) nest-site selection in the temperate forest of southern South America?

GOROSITO, C.A.; TUERO, D.T.; CUETO, V.R.

Journal of Ornithology

Springer

Año: 2024

2193-7206

Nest-siteselection is a behavioral response than can provide protection foradults, eggs and nestlings, affecting fitness. Because predation isthe main cause of nest loss worldwide, it has been considered as themain evolutionary driver in nest-site selection. Nevertheless, insome cases nest microclimate may be the primary evolutionary forceoperating on nest-site selection. We aimed at determining atmesohabitat and microhabitat scales if Chilean Elaenia (Elaeniachilensis)selected the nest site and, if so, whether such selection wasassociated with a reduction in nest predation. Because nestorientation may influence nest microclimate, we also tested whetherit affected the reproductive output. At the mesohabitat scale, thesubcanopy cover (1.5–4 m from the ground) was selected by thisspecies. At the microhabitat scale, elaeniaspreferredSchinuspatagonicusto nest and oriented their nests preferentially to the north andeastern directions. These selected habitat features had no effect onnest success and reproductive output. Despite the risk of nestpredation by several aerial (birds) and ground predators (rodents),both successful and predated Chilean Elaenia nests were close to theground rather than at intermediate heights. Considering the hardnessof S.patagonicus woodthat can provide structural support to the nest against strong winds,and that nests were oriented to the opposite direction of prevailingwind, Chilean Elaenia nest-site selection might be related tomicroclimatic factors at nest sites rather than predation. Therefore,it is imperative to consider potential associations between nestmicroclimate and habitat features to advance in the understanding ofbird nest-site selection.