Retreat, detour or advance? Understanding the movements of birds confronting the Gulf of Mexico

During migration, birds must locate stopover habitats that provide sufficient resources to rest and refuel while en route the breeding or non-breeding area. Long-distance migrants invariably encounter inhospitable geographic features, edges of which are often characterized by habitat limited in food safety. In response, they depart directions inconsistent with reaching their destination, presumably searching for better habitat. We used automated radio telemetry track 442 individuals five species investigate behavior migratory as departed edge along northern Gulf Mexico coast during autumn from 2008 2014. Most (75%) retreated inland detoured around rather than advanced across Gulf, but this depended on bird fat-based energy stores. lean condition smaller bodied tended retreat detour, advance, when departing coast. Twenty-one percent all 2013–2014 were redetected over 45 km inland, providing a unique opportunity compare duration, departure times travel speeds between away those continue advance toward destination. Individuals spent ~1 day before retreating where 11 days resuming migration. Further same coast, evening civil twilight, whereas after twilight. Travel slower compared advancing towards habitats. The differences suggest how an individual's drive feed fly influences behavior. Our study illustrates sum individual decisions can shape use, landscape-scale movements migration strategies.