Biología reproductiva y alimentaria del gavilán de Gurney Geranoaetus poecilochrous en el páramo de Antisana, Ecuador

Abstract

 The breeding and feeding of the Gurney’s Hawk Geranoaetus poecilochrous was studied from 1991- 1994 and with further detail from 2007-2012 in the paramo of Antisana, Ecuador, at 3800 - 4400 m altitude. Of a total of 8 territories at Antisana, 6 (75%) were polyandrous groups and 2 monogamous pairs. Breeding occurred in most months of the year, but 74% of the 27 clutches registered were found in the first six months of the year. Breeding periods of the same pairs or groups had intervals of 6-11 months. The main prey was rabbits (Sylvilagus brasiliensis). Males brought most food to the young. Polyandrous groups remained stable over the four years of study but in one territory there were three different females over a period of 14 years. Males contributed in nest building, incubation and bringing prey to the young. Only one male was observed copulating with a female, the other males in the group were “helpers at the nest”. Of the 15 adults, in five territories, four (26.7%, 3 males, 1 female) were white bellied (light morph), and 11 (73.3%, 4 females, 7 males) were dark-bellied birds (dark morph). Details of four different calls are presented.