Green Sandpiper

The green sandpiper is a somewhat plump wader with a dark greenish-brown back and wings spotted white, a greyish head and breast and white underparts; the spotting is strongest in breeding adults. The short bill and legs are dark green. In flight it is striking, with wings dark above and below and a brilliant white rump, and it gives a characteristic three-note whistle. It belongs to an ancient lineage whose only close living relative is the solitary sandpiper of North America (Wikipedia, general species account).

Unusually for a sandpiper, it nests in trees, laying two to four eggs in the old nest of another bird such as a fieldfare; the eggs hatch in about three weeks. It is very much a bird of fresh water, often using sites too small and enclosed for other waders, and works steadily around the edges of a pond picking small invertebrates from the mud. It is not gregarious (Wikipedia, general species account).