Vegetation height and structure drive foraging habitat selection of the lesser kestrel (Falco naumanni) in intensive agricultural landscapes

Habitat selection in animals is a fundamental ecological process with key conservationimplications. Assessing habitat selection in endangered species and populationsoccupying the extreme edges of their distribution range, or living in highly anthropizedlandscapes, may be of particular interest as it may provide hints to mechanismspromoting potential range expansions.We assessed second- and third-order foraginghabitat selection in the northernmost European breeding population of the lesserkestrel (Falco naumanni), a migratory falcon of European conservation priority, byintegrating results obtained from 411 direct observations with those gathered fromnine GPS tracked individuals. The study population breeds in the intensively cultivatedPo Plain (northern Italy). Direct observations and GPS data coincide in showing thatforaging lesser kestrels shifted their habitat preferences through the breeding cycle.They positively selected alfalfa and other non-irrigated crops during the early breedingseason, while winter cereals were selected during the nestling-rearing phase. Maize wasselected during the early breeding season, after sowing, but significantly avoided later.Overall, vegetation height emerged as the main predictor of foraging habitat selection,with birds preferring short vegetation, which is likely to maximise prey accessibility.Such a flexibility in foraging habitat selection according to spatio-temporal variationin the agricultural landscape determined by local crop management practices may haveallowed the species to successfully thrive in one of the most intensively cultivated areasof Europe. In the southeastern Po Plain, the broad extent of hay and non-irrigated cropsis possibly functioning as a surrogate habitat for the pseudo-steppe environment wheremost of the European breeding population is settled, fostering the northward expansionof the species in Europe. In intensive agricultural landscapes, the maintenance of alfalfaand winter cereals crops and an overall high crop heterogeneity (deriving from crop rotation) is fundamental to accommodate the ecological requirements of the species indifferent phases of its breeding cycle.