86 LOST AND VANISHING BIRDS 



the birds rise in fluttering crowds from the ground, 

 with noisy cries of remonstrance, and continue to 

 fly to and fro above their nests until the danger 

 has passed. But one brood is reared in the season ; 

 and a movement south may be observed soon after 

 the young can fly, the passage of this species 

 extending from August to October, 



The adult Black Tern in summer plumage has 

 the head, neck, breast, and belly black ; the under 

 tail coverts white ; the remainder of the plumage 

 dark grey. In winter plumage the forehead, 

 throat, and lores are white, and the under parts are 

 more or less mottled with white. Young birds 

 have the upper parts, especially on the head and 

 back, mottled with brown. The length of this 

 small Tern is about ten inches. 



