Observations of Red-headed Falcon Falco chicquera (Aves: Falconiformes: Falconidae) nest at Keraniganj, Dhaka, Bangladesh, with a focus on post-fledging behavior

摘要

A nest of Red-headed Falcon Falco chicquera was observed in 2009, beginning with the onset of breeding and continuing on to the next breeding of the pair. The nest was found on 02 March 2009 in an electricity pylon in a sub-urban area at Keraniganj, Dhaka, Bangladesh. The incubation period was estimated at a minimum of four weeks and the nestling period was 37 days. Fledglings remained in the nesting area up to four months after fledging. The female almost exclusively fed the nestlings and fledglings. The diet of adults, nestlings and fledglings consisted of 72% small birds (sparrow sized) and 28% Pipistrellus bats (n = 112). The diet of fledglings consisted of 61% birds and 39% bats (n= 72; before independence mainly birds and after independence mainly bats). Parents delivered prey to fledglings up to 39 days after fledging (i.e., post-fledging dependence period was 39 days). The fledgling’s flight pattern was distinguishable from the adults nearly two months after fledging. The fledgling’s call reminiscent of a begging call was recorded up to 75 days after fledging. Food competition was observed among the fledglings; when one of the fledglings snatched prey from a parent, the other siblings tried to pilfer it. The parents had resumed breeding eight months after the fledging stage of their offspring.