Diet variation of a generalist predator, the American Kestrel (Falco sparverius), in a gradient of agricultural intensification in central Argentina

OROZCO-VALOR, P. M.; GRANDE, J. M.

ACTA ORNITHOLOGICA

MUSEUM & INST ZOOLOGY

Lugar: Warszawa, POLAND; Año: 2021

0001-6454

Agricultural expansion at the expense of natural habitats and the intensification processes in agricultural production are globally among the main causes of biodiversity and ecosystem services loss at large scale. This process can completely alter food provision for birds and have negative consequences on their diet and breeding performance. Under the hypothesis that changes in land use limit food resources for raptors, our aim was to analyze in a population of American Kestrel (Falco sparverius) breeding in nest boxes and cavities, the variation in nestling diet between natural areas and areas with different degrees of agricultural intensification (natural forest, traditional farmland, intensive farmland). Through the analysis of pellets and prey remainscollected during the reproductive season of 2012-2013 we found no differences in diet diversity among areas and the diet in the three areas was monopolized by arthropods. However, the diet did change in composition between areas. Numerically, Orthoptera dominated the diet in the three areas, although with a higher percentage in the forest area. The same trend followed the consumption of vertebrates. In both agricultural areas, the diet was completed with different groups of arthropods suggesting that changes in land use generate a functional response in the American Kestrel that is able to take advantage of available resources in each sampling area. Long-term analysis of diet variation within the framework of agricultural intensification and its relation with demographic parameters and individual performance will allow to evaluate the impact of this variation in the diet for kestrels.