Do Eiders eat sea urchins?
In Iceland in mid-march I saw an Eider playing with what looked like a sea urchin. He dropped it and picked it up four times. Do they actually eat sea urchins? How is he going to cope with the prickles? Debbie Hart, via email
QEiders often eat sea urchins, and spiny ones do feature heavily in their diet, along with other hard-shelled food such as mussels and crabs. Eiders tend to swallow most of their prey whole as soon as it is caught, crushing the shells with their gizzards to make the softer interiors available. However, with crabs and urchins they seem to adopt different tactics. With crabs, the ducks will hold a leg, then shake the crab violently until the body detaches, then swallow the leg and retrieve the rest of the crab before repeating the process. With urchins the ducks are often seen picking them up, rolling them about in their bills, then dropping them before beginning the process again, only swallowing the urchin after three or four drops. It’s thought that the duck does this to loosen or remove the spines, which could possibly cause problems to the Eider on the way down.
Green Heron Black-necked Stilt