Another little-known and rare subspecies of South American endemic has proven to be a 'good species'.
Long thought of as a central Peruvian subspecies of Horned Curassow Pauxi unicornis, new observations confirm that Sira Curassow is different in almost every way.
The new species, P koepckeae, has an entirely separate range, is distinct enough to have a smaller shorter casque than Horned and lacks some of the white markings on the tail that the latter has - the tail is also fanned when the bird is alarmed, behaviour absent from its former conspecific.
Key to the separation of the two species are the differences in song and call, and the two forms also breed several months apart - the new species breeds at the end of the wet season, whereas P unicornis breeds at the start of the wet season. P koepckeae 's alarm call is, however, similar to Horned Curassow.
Sira Curassow was only discovered in 1969 in the Sira Mountains of Peru, where it is endemic. It is a mid-elevation cloud forest specialist, ranging between 1100 and 1435 m - again this contrasts with Horned, which largely lives in lowland and low montane Bolivian humid forest.
In accordance with its reproductive, geographical, ecological and behavioural isolation, the authors suggest elevation to species level, with the English name Sira Curassow derived from its native mountain range. The new species already qualifies as Endangered under Birdlife International criteria, possibly even Critically Endangered as it has a very limited known range which is constantly being degraded by hunters and loggers, despite much of it having National Park status.
Gastañaga, M, MacLeod, R, Brooks, D M and Hennessey, B. 2011. Distinctive morphology, ecology, and first vocal descriptions of sira curassow (Pauxi [unicornis] koepckeae): evidence for species rank. Ornitologia Neotropical 22: 267-279.