THE SOURCE OF THE NUTRIENTS REQUIRED FOR EGG-PRODUCTION IN ZEBRA FINCHES POEPHILA-GUTTATA

The source of nutrients used for egg formation are poorly known for mo st bird species. This study of the zebra finch Poephila guttata showed that food intake did not increase during egg production, but the decl ine in female body reserves of protein and fat were sufficient to acco unt for most of the nutrients in a clutch of four eggs. Female birds s ignificantly reduced their activity levels during ova enlargement, whi ch may play a role in diverting resources to egg production. Birds inc reased their intake of calcium-rich food items when eggs were being la id, and this intake accounted for all the calcium needed for eggshell formation. The zebra finch depends heavily on stored body reserves for egg formation, which is probably unusual in small passerines.