Beyond the breeding grounds: identifying post‐breeding staging areas, corridors and ecological niche of the Lesser Kestrel

The post‐breeding period is a critical yet overlooked phase in the annual cycle of migratory birds, where individuals must resolve competing bioenergetic trade‐offs between recovery from breeding, moult and migratory fuelling. Using GPS data from 54 adult Lesser Kestrels Falco naumanni tracked across Spain, we analysed 76 post‐breeding tracks to characterize movement strategies, the spatial configuration of the staging network and ecological requirements across the Iberian Peninsula. Results confirmed that post‐breeding movements are pervasive, with nearly all individuals departing breeding colonies to undertake medium‐ to long‐distance movements (mean 194.3 ± 107.6 km). We identified a predominantly ‘Staging’ behaviour (80% of tracks) characterized by prolonged residency in specific staging areas (mean 24.9 ± 19.1 days per area), often involving the sequential use of multiple areas (mean two areas per track), and a high degree of inter‐annual fidelity (78%). Spatial analysis revealed a structured connectivity network driven by two high‐density corridors (Northeastern and Western axes) and 149 functional post‐breeding areas (PBAs). Ecological niche modelling (hierarchical generalized additive model) identified wind speed (peaking at 4–6 m/s) and thermal stability as primary descriptors of space use intensity, suggesting a strategy to maximize bioenergetic efficiency and minimize heat stress, while selecting for open rainfed agrosystems (dominated by cereal stubbles) compared with irrigated crops and natural habitats. Our assessment of conservation status revealed a severe protection gap: 52.7% of the functional staging areas have less than 5% of their surface covered by protected areas, while 27.6% of monitored tracks overlapped with wind energy infrastructure. Aligning with recent evidence for other steppe bird species, these findings suggest a migratory adaptation that integrates a distinct intermediate residency phase into the annual cycle to exploit climatically and trophically favourable ‘summer refugia’, shaping a largely unprotected PBA‐corridor network.