Novel insights into the map stage of true navigation in non-migratory wild birds (stone curlews, Burhinus oedicnemus)

In the map-and-compass model of true navigation, animals in unfamiliar sites determine their position relative to a destination site (the map stage) before progressing towards it (the compass stage). A major challenge in animal navigation research is to understand the still cryptic map stage in general, and for free-ranging wild animals in particular. To address this challenge, we experimentally translocated wild, non-migratory birds (Stone curlews (Burhinus oedicnemus)) far from their nests and GPS-tracked their subsequent movements at high resolution and for long durations. Homing success was high, and cannot be explained by random chance or landmark navigation, implying true navigation. Although highly motivated to return home, the homing trajectories of translocated birds exhibited a distinct, two-phase pattern resembling the map and compass stages: a long, tortuous \"wandering phase\" without consistent approach home, followed by a short and direct \"return phase\". Birds re-translocat...