Duck Tales: Spatio‐temporal dynamics of habitat use and prey relationships of a diving duck and its implication for conservation management

Abstract Migratory animals often follow predictable spatiotemporal distributions based on local conditions or resource availability. However, this predictability is frequently not considered in the design of protected areas, resulting in poor alignment between core habitats for migrants and protection measures. This limited overlap hinders the effective protection of threatened migratory species. The common eider (hereafter eider) is a flagship species of the Natura 2000 goals for the Dutch Wadden Sea. However, no specific conservation measures benefitting eiders are in place. We use long‐term spatial data (1993–2023) to model spatiotemporal hotspots of wintering eiders and compare these with the distribution of their preferred prey based on two extensive spatially explicit benthic monitoring programs. We then assess the overlap between the spatiotemporal hotspots and existing general protection measures. Eiders consistently aggregated in small areas (1% of the study area has been a hotspot for over 80% of the study period) and were closely tied to places with high biomass of preferred benthic prey ( Mytilus edulis and Ensis leei ). However, eider hotspots spatially overlapped poorly with current general protection measures. None of the eider hotspots that re‐occur for 80% of the study period are covered by marine protected areas, while dropping this threshold to 20% re‐occurrence yields that only 8% are protected. We present a general method to delineate key areas for migratory animals to inform a more adaptive and effective area‐based conservation strategy that aligns better with the ecological requirements of target species. Applying this method, we find that key areas for eiders in the Dutch Wadden Sea are not well protected despite this being a flagship species for the ecosystem. Our results suggest expanding marine protected areas to the ecologically most valuable zones.