Perched above the fields: density and habitat use of wintering raptors in an intensive farmland area in northern Italy
DOI:
https://doi.org/10.30456/avo.30994Keywords:
alfalfa, Buteo buteo, distance sampling, Falco tinnunculus, habitat preferences, road counts, wintering raptors, roadside biasAbstract
The wintering period represents a critical stage for avian survival and population dynamics. However, systematic monitoring during this phase remains scarce compared to the extensive research dedicated to the reproductive period and migration. To address this gap, we investigated the wintering raptor community in the Parmigiano Reggiano production area in the Province of Parma (northern Italy), a unique agro-ecosystem dominated by perennial forage crops, especially alfalfa Medicago sativa. We conducted roadside car transects during the winter of 2025/2026 to estimate the population density using distance sampling, and to assess the habitat preferences of the two most abundant species: the Common Buzzard Buteo buteo and the Common Kestrel Falco tinnunculus. Survey data indicate a high density for both species, with estimated densities of 2.61 ind./km² (95% CI: 1.71-3.97) for the Common Buzzard and 5.73 ind./km² (95% CI: 4.28-7.67) for the Common Kestrel. The Common Kestrel exhibited a strong roadside bias, requiring left-truncation to obtain unbiased estimates. Furthermore, habitat analysis showed a significant selection for forage crops by the Common Kestrel, confirming the key role of alfalfa in the agricultural matrix. We hypothesize that these densities, among the highest recorded in European lowlands, are driven by the synergy between the extensive availability of favourable habitats (i.e., forage crops) supporting high prey densities, and the increasing frequency of mild winters with no snow cover. This study establishes an important quantitative baseline for future winter monitoring, highlighting the importance of adopting distance sampling methods for effective large-scale bird surveys.
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Copyright (c) 2026 Diego Rastelli, Lara Todeschini, Alessandro Pavesi
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Accepted 2026-05-22
Published 2026-07-15
