Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

Dr Scheibler,Au Christoff

doi:10.1590/s1519-69842007000400005

Abstract

We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba) and White-tailed Kites (Elanus leucurus). Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata) and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758)). The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping) were complementary, since together, rather than separately, they produced a better picture of local richness.

Highlights

Inventories and biogeographical studies of small mammals have been carried out almost exclusively by means of trapping
The identification of prey species from the diet of carnivores or birds of prey can be used to determine the local richness of their prey, there are few studies assessing the richness of small mammals by using and comparing species identified from the diet of predators with those trapped (Jaksić et al, 1981, 1999; Bonvicino and Bezerra, 2003)
Our objectives were to: (1) evaluate the habitat associations of small mammals in an agricultural area of this state; and (2) inventory small mammal species based on prey found in the diet of Barn Owls and White-tailed Kites and to compare these results with trapped samples of small mammals from the same site

Summary

Introduction

Inventories and biogeographical studies of small mammals have been carried out almost exclusively by means of trapping. The Barn Owl (Tyto alba (Scopoli, 1769)) is a cosmopolitan nocturnal bird of prey that hunts mainly in fields (Fast and Ambrose, 1976; Bellocq, 1990, 2000). It preys primarily on small mammals (Jaksić et al, 1982; Marti, 1988; Bellocq, 2000). The White-tailed Kite (Elanus leucurus (Vieillot, 1818)) is a diurnal bird of prey distributed throughout the Americas (Dunk, 1995) This kite is a small mammal specialist, hunting in open environments such as fields and savannas (Mendelsohn and Jaksić, 1989; Dunk, 1995)

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