
Description and Distribution
Eurasian whimbrels are medium sized waders in the family Scolopacidae and a member of the curlew genus, Numenius, which contains 9 species. They have a bill that curves at the end, making them particularly effective at picking around in the mud looking for worms and other invertebrates.
The Eurasian whimbrel is easily mistaken for the Eurasian curlew except for the fact that whimbrels have shorter bills, are a bit smaller, and have more pronounced stripes on the head. Otherwise its plumage consists of speckled brown and grey upperparts.
They are one of the most widely spread of all curlews, breeding in subarctic Asia and Europe and then migrating to basically the rest of the coasts of the world including Africa, South Asia, Austrailia and New Zealand.
The North American variety of whimbrel has recently been split into a subspecies, the Hudsonian whimbrel, although its distinguishing features are limited, and some experts still consider them to be the same species.

Behavior and Ecology
Whimbrels’ curved beaks are especially adapted to extracting fiddler crabs from their holes, which makes up a large portion of their diet. They are able to dip their bills into the crab’s hole and pull it right out, often slamming the crab on the ground in order to dismember it before then eating the rest.

I have only witnessed this bird in groups of up to 8, so I am not sure how large migrating groups can get. Otherwise though they seem not to be very gregarious during migration, opting to travel in small flocks rather than

Evolutionary History
A fossil from the Montmarte Formation of a species Limosa gypsorum is thought to be an ancestor of both curlews and godwits, having existed some 35 million years ago. It is also believed that curlews and godwits are more basal and primitive than other sandpipers.