Arboreal Dead-Leaf-Searching Birds of the Neotropics

Abstract

At least 11 species of birds in northern Bolivia and southern Peru are dead-leaf-searching "specialists": more than 75% of our foraging observations of these species have been of individuals searching for insects in dead, curled leaves suspended above ground in the vegetation. All known specialists of this kind belong to the families Furnariidae and Formicariidae. An additional six species, here called "regular users," exhibit dead-leaf-searching behavior in 25% to 75% of our foraging records. The number of specialists and regular users decreases with rising elevation in the Andes. Specialists disappear from the gradient between 2,000 m and 2,575 m, but regular users occur as high as 3,300 m, near timberline. As many as eight species of dead-leaf-searching specialists coexist in western Amazonia.