Relação da dieta e Helmintofauna de sete espécies de corujas da região sul do Brasil

Abstract

Owls are nocturnal birds of prey that play a fundamental ecological role as top predators in various ecosystems. By consuming a wide range of prey and occupying both urban and natural environments, these birds directly reflect environmental changes, revealing complex ecological interactions that, until recently, were largely unexplored in terrestrial habitats under strong anthropogenic influence. Studies on their diet and parasitofauna allow us to understand not only trophic interactions but also the impacts of anthropogenic factors such as pollution and habitat fragmentation. In this context, the integrated analysis of stomach contents and helminths in owls offers an effective approach to assess ecosystem health and monitor the effects of human activities on wildlife. This thesis aimed to characterize, in an integrated manner, the diet and helminth fauna of seven owl species found in conflict situations along the coastal region of Santa Catarina, Brazil. For this purpose, data were collected from necropsies of 64 individuals found along the BR101 highway between 2006 and 2021. Stomach content analysis revealed a generalist and opportunistic diet, composed mainly of insects and small mammals, with interspecific variation. Plastic fragments were also detected in the digestive tract of all analyzed owls, indicating accidental or indirect contact with urban waste—an unprecedented finding that positions these birds as new sentinels of terrestrial pollution. The helminth fauna included representatives from the groups Nematoda, Cestoda, Digenea, and Acanthocephala, with significant differences in prevalence and parasitic load among species. Parasite richness showed a correlation with dietary diversity, indicating that diet directly influences the composition of acquired parasites. The presence of mesoplastics in wild owls reinforces the impact of human activities on ecosystems and highlights the importance of these birds as bioindicators of environmental health. The combination of classical necropsy methods with ecological and parasitological analyses demonstrates the potential of rescued carcasses as valuable data sources for monitoring wildlife and understanding the relationships among environmental contamination, feeding behavior, and parasitism. These results confer a strategic role to owls in the study of trophic networks, parasitic cycles, and environmental impacts in fragmented areas.