Wintering Red Kites in Central Spain: Macrohabitat Selection and Population Density Estimate
by
, , and
Alan Omar Bermúdez-Cavero
1,*,
Edgar Bernat-Ponce
2,
José Antonio Gil-Delgado
3 and
Andrés López-Peinado
4 1
Dirección de Humanidades, Campus Ica, Universidad Tecnológica del Perú, Av. Ayabaca S/N, Ica 11001, Peru
2
Faculty of Health Sciences, Universidad Europea de Valencia, Paseo de la Alameda, 7, 46010 Valencia, Spain
3
Department of Microbiology and Ecology, Terrestrial Vertebrates Ecology, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/Catedrático José Beltrán, 2, 46980 Paterna, Spain
4
Independent Researcher, Casillas de Ranera, 16321 Cuenca, Spain
*
Author to whom correspondence should be addressed.
Birds 2025, 6(4), 54; https://doi.org/10.3390/birds6040054
Submission received: 1 September 2025
/
Revised: 7 October 2025
/
Accepted: 10 October 2025
/
Published: 13 October 2025
Simple Summary
The Red Kite is a bird of prey found mainly in Western Europe. Once common in Spain, its numbers have declined sharply over the past two centuries, and by the late 1900s, it had nearly disappeared as a breeding species. While conservation projects have supported the recovery of this species, identifying its wintering locations remains crucial for effective protection. We studied Red Kites in and around the La Mancha Húmeda Biosphere Reserve, a wetland and farmland area in Central Spain. Using over 300 vehicle surveys along both paved roads and dirt tracks during the winters of 2021–2022 and 2022–2023, as well as the 2022 breeding season, we estimated Red Kite density through Distance sampling and compared habitat types. We found no difference in density or detectability from roads versus tracks. In total, 124 birds were seen in winter, but none were observed during the breeding season. This suggests that the reserve hosts a wintering population of around 1400 kites. Spain hosts ~50,000 wintering Red Kites, nearly three-quarters of the European population, with the study area holding 5% of this total. Red Kites favor diverse farmlands over rugged areas, making habitat protection and improvements in heterogeneous agricultural landscapes essential for their recovery in Spain.
Abstract
The Red Kite (Milvus milvus), a Western Palearctic raptor, experienced a severe population decline across its range during the 19th and 20th centuries, nearly disappearing as a breeding species in Spain. Although conservation and reintroduction efforts have facilitated recovery, information on its wintering ecology remains limited. We evaluated the population size and habitat selection of wintering Red Kites in and around the La Mancha Húmeda Biosphere Reserve (MHBR), Central Spain, and assessed whether survey route type affected detectability. Surveys comprised 325 vehicle-based line transects along paved roads and dirt tracks during the winters of 2021–2022 and 2022–2023, and the 2022 breeding season. Detection rates and density did not differ between route types. Across 212 winter transects, we recorded 124 individuals, with none detected during 113 breeding season transects. Density estimates were consistent across winters (1.3–1.4 individuals/km2), yielding a population estimate of approximately 1430 individuals. Habitat analysis indicated clear selection for open agricultural mosaics dominated by fallow land and vineyards, while rugged terrain was avoided. These results identify MHBR as an important wintering area. Yet, super-intensive agriculture is a poor habitat due to its uniformity. Enhancing heterogeneous open landscapes, including farmland, is essential for Red Kite colonization and expansion.
