234 THE BIRDS OF THE BRITISH ISLES. 



tail depressed and expanded, and bill pointed seaward, then 

 half closing its sharply angled wings, dives obliquely, often 

 with a slight screw twist, entering the water with a splash. In 

 a second it is up again, for frequently its wing tips are not 

 submerged, and rises with or without a struggling fish. It 

 sports in the air with companions, the call kierie, or a sharp kit, 

 often changed to pieri-e of mock annoyance ; a clamour of 

 voices announces the discovery of a shoal of fry, and excited 

 terns hurry from all directions, hover, a snowy cloud, and rain 

 upon their silvery victims. Terns rest upon the shore, but 

 walk little and badly ; the crossed tips of the long wings are 

 usually held well above the tail. They are easy though not quick 

 when swimming, but are certainly most at home in the air. 



Towards the end of April the immigrants arrive, for they are 

 summer visitors ; many travel overland and halt to feed on 

 inland waters ; there they catch insects as well as fish, swooping 

 gracefully and taking them on the wing either from or near the 

 water. From the middle of May until August they remain near 

 the nest colony, but by the end of September most have left 

 our shores, though passage birds drift through in October. 

 Young birds when able to fly wander at first ; ringed Common 

 Terns have been recovered in their first autumn far to the 

 north of the ternery, though others have been reported in 

 France and Spain. The breeding colonies are in various 

 situations ; three of the largest that I have visited are on 

 coastal dunes, others on rocky islets, where thrift, wild beet, 

 and tree-mallow is the only vegetation. One colony was on 

 gutter intersected saltings, the nests on the sheep-cropped 

 grass or in beds of sea-aster ; I doubt if it survived the next 

 high tide, for it had been submerged shortly before my visit. 

 Other colonies are on shingle or the sand above high-water 

 mark. 



Nests may be lined or unlined, eggs being laid on bare rock 

 or soil, in neatly rounded depressions, or in nests of consider- 



