Determinação de espécies de presa de corujas através de análises de ossadas, dentaduras e pêlos extraídos das pelotas

Abstract

As they are at the top of the food chain, owls are considered important agents in the dynamics of natural populations of various types of prey, especially small mammals. Studies on the biology and feeding habits of owls are lacking in Mozambique. For that reason, the aim of this study was to evaluate the owl prey spectrum. The material for the study of the predator's diet consisted of 75 regurgitated pellets collected from close to minhos and perches. Bones, dentures, parts of the exoskeleton and hair from the prey were extracted from the poles. From the analyzes carried out on the contents of the pellets, it was found that T. alba produces pellets with a smooth, rough and irregular texture, while B.africana only produces rough and irregular pellets. Analyzing the volume of the pellets, it appears that the volume of the pellets increases with the number of prey, as well as with the biomass contained in the pellets. From the analysis of bones, skulls, dentures, parts of the exoskeletons and hair extracted from the pellets, 161 prey items were identified, represented by rodents, shrews, bats, birds, a lizard and insects. Rodents were the most important prey in terms of frequency and biomass consumed by owls. Both T. alba and B. africana showed a clear selection trend for S. pratennis rodents. In addition to selecting prey species, owls also showed preferences for particular prey sizes. B. affricanas, the largest predator, consumed large prey and T.alba, the smallest predator, consumed smaller prey. The birds and the lizard seem to be used as a complement to the consumption of mammals by B. Africans. The high incidence of rodents in the diet of T. alba and B. africanus suggests that these owls are specialist rodent predators and, consequently, in the preservation of natural ecosystems. The present work is a contribution to the study of the biology and ecological aspects of T. alba and B africanus in Mozambique.