Diet of the Loggerhead Shrike (Lanius ludovicianus) and importance of living fences in an agricultural landscape in Veracruz, Mexico

Abstract

The Loggerhead Shrike (Lanius ludovicianus) is a carnivorous bird whose diet consists mainly of insects and, to a lesser extent, vertebrates. Although common in agricultural areas, the species has shown a population decline. In May 2012, we analyzed the diet of a pair of shrikes through prey found impaled along a barbed wire fence and agave plants (Agave salmiana) in the semi-arid region of the Perote Valley, Veracruz, Mexico. We recorded 18 prey species: nine vertebrate species (five birds, two mammals, and two reptiles) and nine insect species. Fifty-eight percent of the prey were found on barbed wire, while 42% were found on the apical spines of agave plants. We reviewed 32 papers that report vertebrates as part of the Loggerhead Shrike's diet, compiling a list of 81 vertebrate prey species, with greatest diversity of prey in the orders Squamata (35) for reptiles and Passeriformes (24) for birds, followed by Rodentia (8) for mammals. We observed a similar pattern in our study, where most vertebrate prey belonged to these three orders. Our results indicate that living fences of agave are important elements for maintaining the Loggerhead Shrike in these agricultural landscapes, as they serve as perches and as sites for hunting and storing prey.