Lesser kestrel diet and agricultural intensification in the Mediterranean: An unexpected win-win solution?

Abstract

Farmland bird species have suffered dramatic declines in recent decades, especially in Mediterranean areas. The intensification of agricultural practices has led to reduced invertebrate prey, which represent the bulk of the diet of many farmland birds. In this study, we investigated the spatial and temporal variation in the diet of the lesser kestrel (Falco naumanni) during the breeding season, monitored over a five-year period between 2006 and 2013 in the Gela Plain (Sicily). Our aim was to understand whether, and to what extent, farming practices affected the reproductive outputs of this predominantly insectivore bird in order to find a profitable compromise between conservation of farmland birds and farming practices. During our study, lesser kestrel diet varied among farmland habitats, in terms of ingested biomass, prey items/pellet and diet breadth. This has reflected in the reproductive output because colonies characterised by a higher ingested biomass fledged more chicks than the others. The artichoke and grassland fields were found to provide the most beneficial dietary parameters. Unexpectedly, the intensive and high-profit artichoke farming might turn out to be suitable for lesser kestrels. Artichoke fields are chiefly used when abandoned after harvest, providing high prey availability and accessibility for kestrels during the brood raising stage of their breeding season. A mosaic of grassland and artichoke fields can thus be recommended for Mediterranean agricultural areas of the Natura2000 network, in which some intensive farming and lesser kestrels can coexist, if adequately framed in a friendly-to-wildlife agriculture policy. Such a potential optimal trade-off between avian population persistence and economic sustainability for farmers we have found, should be planned in alternative management of agro-ecosystems, enhancing the functioning of trophic chains. For our study area, we suggest at least farmers be: i) informed on the role of predators as biological agents for pest control; ii) granted to reduce the high level of chemicals currently used during cultivation in favour of organic farming; and iii) granted to maintain the artichoke fields until June, following completion of the harvest.