Small mammals in the diet of Barn Owls (Tyto furcata) in an urban area in Rio de Janeiro state, Brazil, with a new record of the dwarf mouse opossum (Cryptonanus)

A J Almeida,R R Ribeiro,H V R Dias,V C Silva,P R Gonçalves,A B F R Godinho,K S Rangel,I C V Borges,J A Maia-Júnior

doi:10.1590/1519-6984.237675

Abstract

Abstract Several studies emphasize the use of owl pellets in small mammal inventories in natural areas harboring high richness of rare species, but few Brazilian Atlantic forest localities have been surveyed by this method. The present study documents the species composition and abundance of small mammals in the diet of Tyto furcata in an urban area of the municipality of Campos dos Goytacazes, Rio de Janeiro, Brazil, remarking on a new record of the dwarf mouse opossum genus Cryptonanus in the Atlantic forest. We analyzed 265 pellets regurgitated by a pair of T. furcata from November 2016 to September 2017 found in a nesting box. Analysis of the samples enabled finding a total of 596 individuals of four small mammal species. Mus musculus was predominant among the prey items (98.3%), while the native rodents Necromys lasiurus (1.3%) and Holochilus brasiliensis (0,17%) were much rarer. A single specimen of Cryptonanus sp. was identified among the diet items based on distinctive dental characters. The identification of this genus in the present study represents the second record in the state of Rio de Janeiro, and the sixth in the Atlantic Forest biome, suggesting that this marsupial occupies a wider ecological and biogeographic range. The present study underscores the relevance of owl pellets for small mammal surveys, even in urban and highly disturbed areas.

Highlights

Owls are members of the Strigiformes, an order with two families, the Strigidae and Tytonidae (Robert Ridgway, 1914)
We analyzed 265 pellets regurgitated by a pair of American barn owls (Tyto furcata), naturally nesting in the yard of a residence located in an urban area of the municipality of Campos dos Goytacazes, Rio de Janeiro from November 2016 to September 2017, located at Atlantic Forest area (Figure 1)
We identified 596 individuals (Table 1) from one species of marsupial, the dwarf mouse opossum Cryptonanus sp., and from three species of rodents, the house mouse Mus musculus, the pixuna field mouse Necromys lasiurus, and the marsh-rat Holochilus brasiliensis (Figures 4 and 5)

Summary

Introduction

Owls are members of the Strigiformes, an order with two families, the Strigidae and Tytonidae (Robert Ridgway, 1914). The American barn owl, Tyto furcata, has great importance for the biological control of rural and urban pests of public health interest, as it preys on species that are harmful to human health and agriculture, like invasive. Since the main prey of Tyto furcata are small mammals, especially rodents and marsupials, the diet of these owls reflects the composition and abundance of local prey species (Jaksic et al, 1982; Ebensperger et al, 1991; Clark-Junior and Bunck, 1991; Love et al, 2000). Owl pellet studies are still rare in the Brazilian Atlantic forest, especially in Rio de Janeiro state (Romano et al, 2020)

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Conclusion