202 THE BIRDS OF THE BRITISH ISLES. 



non-breeding birds feed on the shore when the residents are 

 nesting ; in winter, when the migrants have arrived, the flocks 

 are often immense. With the advance of the tide they pack 

 on the lessening banks, or crowd on reefs and islets, and when 

 forced to move rise with a chorus of calls, kleep^ kieep, kleep, 

 and fly, low over the water, to a drier refuge. When they 

 settle, the clamour rises in volume for a few seconds and then 

 dies away. Long before the flocks break up in spring, the 

 amorous males may be seen running on the banks or standing 

 in groups with heads lowered and bills touching the ground, 

 piping the trilling nuptial song. W^hen the tide falls the birds 

 scatter over the ooze or rocks, plunging the bill deeply for 

 cockles or worms, or wading over the still submerged mussel- 

 scalps to catch their victims before they close their valves. 

 There is little evidence that the bird ever opens oysters, but it 

 forces back the valves of mussels and smaller bivalves with 

 skill, as well as smartly knocking the unsuspecting limpet from 

 its hold. On rare occasions a bird will fly up with a shell and 

 drop it on hard sand or rock until it is fractured. Crabs and 

 other crustaceans and small fishes are eaten. The call is a 

 clear, ringing feet^feet, and the alarm a sharply emphasised and 

 repeated //V, /^V, //V. Nesting birds are bold, mobbing human 

 beings as well as avian visitors ; I have seen a pair drive away 

 a Carrion-Crow, and another pair, when guarding young, chased 

 the passing Herring-Gulls until they squawked in alarm, dodging 

 the fierce assailants. They even flew out over the water to mob 

 a passing steamer I 



The choice of the nesting site varies considerably, as does 

 the quantity and quality of the nesting material. In England 

 and Wales the nest is usually near the shore, but in Scotland 

 the bird also nests on the banks of rivers and lochs. I have 

 found nests in the middle of a field, on the clifl" edge, on rocky 

 reefs and islands, on sandhills and pebble ridges. I have seen 

 them unlined, or with a plentiful lining and wall of bents or 



