Cuckoos are summer visitors to the UK from tropical Africa. They arrive between mid April and early May, when you can hear their well-known cu-ckoo call in most parts of the countryside - though the birds themselves can be hard to spot.
Cuckoos come to Britain to breed, and in this respect, they have a crafty strategy. Instead of building their own nest, they use the nests of ‘host’ birds. When a female cuckoo finds a suitable nest, and the hosts aren’t looking, she removes one of their eggs and lays her own egg in its place.
Cuckoos are one of the most tenable harbingers of spring; their distinctive cu-ckoo call allied with the lengthening of the day give the sense that spring is once again upon us. If you have heard them, you can let us know by plotting your location on the map below.
World Class are twinning schools along the route of the Cuckoo so if you've got a school in Britain and you want to find a school in Africa to twin with, you can find more information at the World Class website.
How many cuckoos are expected in the coming months? Stephen Moss finds out here.