CONOPOPHAGIDAE GNATEATERS FAUNA PARAGUAY

CONOPOPHAGIDAE - GNATEATERS

A single species in this exclusively Neotropical family occurs in Paraguay. The origin of the family name is from the Greek meaning, unsurprisingly, "Gnateater". The group has long been considered by taxonomists to be closely-related to the antbirds and DNA-DNA hybridisation analysis has reinforced that position. All described species belong to the genus Conopophaga and there are no subfamilial distinctions currently recognised in the Conophagidae.
The Gnateaters are an unobtrusive and under-studied family of birds and very little is known about their biology. They occur in forest undergrowth, usually within 1.5m of the ground, though only occasionally descending to the ground itself. Typical Gnateaters are small, stocky birds with large heads and a short tail. The wings are short and rounded and the legs are long. The flattened bill is slightly hooked at the tip. The outer 2 or 3 primaries of males are modified which enables a whirring noise to be produced in flight. Studies in Brazil suggest that full wing moult lasts around 2 to 3 months. All species have plumes in the postocular region which are usually concealed by the crown feathers, but can be revealed suddenly - probably having a signalling function in the dark undergrowth of the forest. When on the ground they move by hopping, frequently flicking the wings. They are very vocal, singing most often at dawn, but also producing a series of other calls - one of which that sounds like a person sucking their teeth is responsible for the common Spanish name "Chupadientes" or "Tooth-sucker".
Gnateaters live in pairs year-round and do not join mixed species flocks. They scratch the head via the indirect method, lifting the foot up over the wing. The diet consists almost exclusively of arthropods. The two most common methods of capturing food involve perching on a low branch and jumping to the floor to capture prey, or reaching upwards and gleaning from foliage. Only very rarely do they take prey in flight. Large prey items may be beaten against a branch before swallowing, but the feet are never used to hold or manipulate food.
Gnateaters are considered monogamous and seasonal breeders. Nests are a shallow cup located in a supporting network of thin branches camouflaged with plant material, invariably within 1.5m of the ground. Two buffy eggs are laid with darker spotting towards the obtuse end. Sitting birds are reluctant to flush. Both sexes incubate and care for the young. The Paraguayan species is only slightly sexually dimorphic.

REFERENCES
Campbell B & Lack E 1985 - A Dictionary of Birds - T & AD Poyser.
Whitney BM 2003 - Conopophagidae Handbook of the Birds of the World Vol 8 - Lynx Ediciones.