Parental care of Elaenia albiceps nestlings in the Andean-Patagonian Forest.

CRISTIAN GOROSITO; DIEGO T. TUERO; VICTOR R. CUETO

Congreso; Ornithological Congress of the Americas. XVII Reunión Argentina de Ornitología. XXIV Congreso Brasilero de Ornitología. XCV Association of Field Ornithologist Meeting; 2017

Most bird species provide biparental care, which is mainly associated with monogamous species with altricial nestlings. Biparental care is not always equally shared between sexes, and the female is the one that provide more parental care. Our objetive was to research parental care inElaeniaalbiceps, which is a migrant species that reproduces in the Andean-Patagonia Forest during the austral summer. The study took place in Esquel, Argentina, in two breeding seasons (2015/2016 y 2016/2017). E. albiceps nests were filmed during 45-90 minutes when the nestlings were 2-4 days and 9-10 days old (they were close to becoming fledglings). The provisioning frequency of nestlings by females was higher than the one for males, and both sexes increased their provisioning frequencies with the age of nestlings. The unassisted females that fed nestlings had the same provisioning frequency than the females assisted by males. We differentiated males that did not provide parental care, males that had contributed very little to parental care and males that had provide as much parental care as females. Our results indicate that E. albiceps has a marked biparental care biased to females, and females can raise a brood without contribution of the male. The great variance in parental care observed among males is compatible with a monogamous mating system with a low paternity certainty, therefore further studies about the rate of extra-pair fertilizations will allow us to assess this hypothesis.