Study of the food habits of Tyto furcata (Temminck, 1827) and Pulsatrix koeniswaldiana (Bertoni & Bertoni, 1901) through analysis of the stomacal content

The owls play an important role in trophic relationships, however, studies on the diet of these organisms are still scarce. The Tyto furcata and Pulsatrix koeniswaldiana diets were evaluated by the stomach contents analysis of 50 individuals (n = 25 to Tyto furcata and n=25 to Pulsatrix koeniswaldiana) deposited in the Zoological Collection of FURB (CZFURB). The items were identified to the lowest taxonomic level possible. For mammals the skulls, jaw and dentition were used; for birds, the skull and feathers were used; for amphibians, the bones of the postcranial skeleton were used, which were compared with specimens deposited in CZFURB. Identification keys were used for invertebrates. We found 127 food items, 50 to T. furcata and 77 to P. koeniswaldiana. Feeding diets differed statistically (Student’s t-test, p <0.0001). The diet of T. furcata was predominantly composed of rodents species (58%), particularly Oligoryzomys sp., Mus musculus, Akodon montensis and Rattus rattus. Further, other items consumed by this species was invertebrates (36%), birds (4%), and amphibians (2%). The invertebrates of the Coleoptera and Orthoptera orders were the most consumed by Pulsatrix koeniswaldiana (71%), followed by mammals (14%), by birds (12%) and amphibians (3%). In relationship to the biomass consumed, the rodents were more representative in the T. furcata diet, totaling 71.44%. Also, the diet of P. koeniswaldiana, despite the higher frequency of invertebrates, mammals and birds were the most representative of biomass, with 57.46% and 36.89%, respectively. The differences found may be associated with the environment in which each species lives and the availability of the resource.