Avian-lizard saurophagy: an unusual predatory behaviour of the Southern House Wren in an urban area of the Brazilian Cerrado

Many lizard-eating birds in tropical ecosystems are primarily insectivorous. The Southern house wren (Troglodytes musculus) is a small-sized diurnal bird species that is distributed throughout South America where it is found in both anthropized areas and natural habitats. Although T. musculus feeds mainly on insects, we report an unusual predatory behaviour for this small-sized insectivorous bird — preying upon a juvenile lava lizard (Tropidurus hispidus) on the ground, in an urbanized area of the municipality of Teresina, central-northern Piauí State, Northeast Brazil. Lizard predation is a new feeding behaviour for T. musculus and may be related to seasonal variation in the availability of food resources and predation risk. The only species of Troglodytes for which lizard predation has been reported is Troglodytes aedon, so this represents the first record of a lizard in the diet of T. musculus. Further studies are needed, however, to determine the frequency of saurophagy in populations of this insectivorous bird species.