On 23 March, our bird guide Cirilo Vieira was guiding two guests David Wilcove and Tim Treuer from Princeton University at Pico da Caledônia who were keen to see the rare Grey-winged Cotinga Tijuca condita found in the elfin forest around the top of the mountain. Unfortunately they could only hear the cotinga calling, but then imagine their surprise when they caught sight of an Orange-breasted Falcon Falco deiroleucus perched on a bare branch close to the road (just a few hundred metres from the checkpoint at the start of of the starts to the summit). David had been looking for this bird for 30 years and sighed in disbelief when he realized what it was!
Orange-breasted Falcon is very similar in appearance to the much more common and widespread Bat Falcon Falco rufigularis. Identification can be difficult, but there are some key identification features if seen well. Structurally, Orange-breasted Falcon is larger and bulkier than Bat Falcon and with a larger head and slightly shorter graduated tail. The feet are also noticeably larger and are yellow to greenish-yellow compared to the bright orange-yellow feet of Bat Falcon, and the bill is significantly heavier. Orange-breasted Falcon has blackish upperparts that contrast very little with the blackish head, whereas across much of it’s range, Bat Falcon generally has paler greyish upperparts that contrast with the blackish head.
There are several supporting identification features, that while not diagnostic, are also useful. In Orange-breasted Falcon the white throat is bordered by an orange breast (above the black ‘vest’ on the belly) and neck sides, whereas in most Bat Falcons the white throat contrasts strongly with the black vest with little or no orange or buff on the breast (there are some exceptions though so this alone is not a reliable identification feature). Also, the whitish barring on the black vest is coarser with an orange wash on Orange-breasted Falcon compared to Bat Falcon that usually shows faint narrow whitish barring on the vest.
The Neotropical Bird Club website has an excellent paper on the identification of Orange-breasted and Bat Falcons.
Guilherme Serpa informs us that this is only the second sighting of Orange-breasted Falcon for Rio de Janeiro state – an incredible record! Intriguingly, Adilei has seen a falcon here in the past that he assumed was Bat Falcon and Nicholas has photographs of a falcon taken nearby on Pico da Caledônia, again presumed Bat Falcon at the time. We will be checking these photos to double check the identification.
The following day another group from the lodge visiting Pico da Caledônia failed to relocate the bird, but hopefully it will be seen again. Very well done to David Wilcove for an excellent state find and for taking an excellent set of photographs.