The henna-capped foliage-gleaner Hylocryptus rectirostris is an endemic bird of the gallery forests of the Cerrado region of central South America. The species is considered rare to uncommon and a priority for research. The lack of apparent sexual dimorphism is the common pattern Furnariidae family. However, sexual size dimorphism was found for some species of this family, suggesting evolutionary pressures and distinct ecological requirements between males and females. The aim of this work was to verify the existence sexual size dimorphism in a population of H. rectirostris at 'Parque Nacional da Serra do Cipó', Minas Gerais. We took seven body measures of 21 individuals (13 males and eight females) captured from April 2004 to November 2005. Each individual was sexed using molecular sexing techniques. The males had significantly larger wings and tails than females (wing: U = 5.5, p = 0.0008; tail: U = 8.0, p = 0.0014). These results clearly shows the differences of each sex. These differences seem to be related to territorial defense, a male duty in most of the time, who hold territories throughout all year long, even in the absence of a partner. Longer wing and tail increase flight performance, favoring those bigger individuals during the acquisition and defense of territories, female attraction and consequently enhancement of reproductive success.
Morphometric; sexing; tail; territory; wing
