New species of forest-falcon

Forest-falcons Micrastur are small Accipiter-like raptors occurring in tropical forest in most of South America. Until recently, six species were recognized. Four species are widespread and common, whereas two have more restricted ranges and are considered rare. Forest-falcons are vocal but very secretive and hard to observe. Therefore, populations have often been underestimated and for most taxa, little is known about breeding and behaviour. With this in mind, it may not come as a big surprise that studies by Andrew Whittaker revealed the existence of a hitherto undescribed species, Cryptic Forest-falcon M mintoni, inhabiting the rainforests of Brazil and adjacent north-eastern Bolivia (Whittaker, A 2002. A new species of forest-falcon (Falconidae: Micrastur) from southeastern Amazonia and the Atlantic rainforests of Brazil. Wilson Bull 114: 421-445).
The initial detection of the cryptic new taxon was triggered by its distinctive voice, first heard and recorded by the author on 28 October 1997 at Caxiuanã, Paná, Brazil; this voice is notably different from any of its congeners. The bird responded to play-back of its own voice and was noted to differ in several aspects from other forest-falcons. Several specimens of the new taxon were subsequently located in museums; because the new species closely resembles Lined Forest-Falcon M gilvicollis, these specimens had remained unrecognized for more than a century. The new taxon not only has a vocal repertoire that differs from those of its congeners, Lined Forest-Falcon, Plumbeous Forest-Falcon M plumbeus and Barred Forest-Falcon M ruficollis, but also exhibits subtle yet consistent morphological distinctions - especially in the pattern of head, underparts and tail - that distinguish it from all other forest-falcons. There are also differences in biometrics. The species inhabits humid terra firme forest in south-eastern Amazonia, and a disjunct population exists in the Atlantic rainforests of eastern Brazil (the latter known only from historic specimens) and merits great conservation concern.
The species has been named after Clive D T Minton, friend and birding mentor of the author. The English and Portuguese name (Falcão Cryptico) refer to the fact that this taxon has remained undetected for so long, despite specimens being present in several collections and despite the fact that it is not uncommon within its now known range.
Enno B Ebels