The Cuckoo, known as the Common Cuckoo outside the UK to distinguish from other birds in the cuckoo family,
is well-known for the call after which it is named, for its summer migration to Europe/Asia from its wintering grounds in Africa/South Asia
and for being a brood parasite (laying its eggs in the nests of other birds).
The adult male, top row left is grey with hawk-like grey bars on its front.
The adult female is also usually grey, the hawk-like appearance helping her to access the nests of small birds.
Rarely, the adult female Common Cuckoo is rufous brown, known as "hepatic phase" after the colour of liver.
The hepatic phase brown Cuckoo above is overlooking a reed bed, waiting for the resident Reed Warbler to leave the nest long enough for the
Cuckoo to lay an egg beside the host's eggs. The tiny Reed warblers, together with Dunnocks and Meadow Pipits, are favoured hosts.
The feet are yellow, as are usually the base of the bill and the eye-ring.
Juvenile Cuckoos can also be brown, as shown above.
All photos on this page except the top row centre and row 3 are by Alexandra Makhnina.
She says that the juvenile above was begging for food from its foster parent who was a masked wagtail.