... is lower in caged birds than in birds trapped while flying at night. Bird migration Melatonin Stopover Captivity Erithacus rubecula Most migratory passerines are nocturnal migrants, in that they have usually diurnal patterns of activity but become active at night during migration...

... of the catabolism of protein. At stopover sites, birds need 2–3 days to rebuild their GIT so that they can restore body mass and fat reserves to continue migration. The source of protein used to rebuild the GIT may be exogenous (from food ingested) or endogenous (reallocated from other organs) or both. Because...

... showed that hypothermia of this magnitude can lead to a reduction of some 30% in energy expenditure compared with birds remaining normothermic. Our data suggest that by reducing the T b – T a gradient, blackcaps accelerate their rate of fuel accumulation at a stopover. When body energy reserves are low...