Use of regurgitated pellets of barn owl (Tyto alba) for inventorying small mammals in the Cerrado of Central Brazil

Analysis of regurgitated pellets of one barn owl (Tyto alba; Strigiformes, Tytonidae) collected in the Cerrado of central Brazil yielded remains of 12 vertebrate species comprising eight rodents, two marsupials, one passerine bird and one lizard. A survey of small mammals in the same region with 3,367 trap nights revealed 11 rodent and two marsupial species. Seven of the 16 small mammal species found in the region were sampled by both methods. Two marsupial and one rodent species in regurgitated pellets were not captured with traps while two marsupial and four rodent species captured with traps were not found in regurgitated pellets showing that these two survey methods are complementary. Regurgitated pellets of T alba can be a good source of information for assessing the species richness of small mammals but are biased by the feeding habits of the bird hunting predominantly small mammals in open habitats. Together with the results of trappings our study revealed a prominent richness of small mammal species in the Cerrado of south-western Bahia.