![Figure][1] A gray catbird in Dry Tortugas, Florida, USA, during the spring migration. Photo credit: Jeremy Cohen. It takes a lifetime of toil to look like Mr Universe, but migrating… Click to show full abstract
![Figure][1] A gray catbird in Dry Tortugas, Florida, USA, during the spring migration. Photo credit: Jeremy Cohen. It takes a lifetime of toil to look like Mr Universe, but migrating songbirds seem to be able to pile on muscle – and fat to power their migrations – with no effort at
               
Click one of the above tabs to view related content.