Perfect timing

Dunlins reach the UK in three waves

The secret of successful migration is timing. If birds leave too early, they may run out of energy before finishing their journey. If they leave too late, they may run into bad weather along the way.

Each species has its own schedule. Adult cuckoos are off by August. Their parental responsibilities ended as soon as they laid their egg in another bird’s nest, so they have no reason to stay. House martins may hang around until October. They have to wait until their second – or even their third – brood has fledged, before the whole family heads south together. 

Leaving in waves
Birds of one species do not all migrate together. With many wading birds, the females set off first, leaving the males to stay behind and raise the chicks. The males leave as soon as the chicks can fend for themselves. Dunlins from Greenland reach the UK in three waves: first the females in July, then the males in August, and finally the young in September.