320 BIRDS OF NEW ENGLAND AND EASTERN NEW YORK 



September. Along those parts of the coast where it does 

 not breed, it is seen as a migrant in May, and more com- 

 monly in August and September. Many young birds may 

 be found in late summer congregating on beaches at some 

 distance from the nearest breeding-ground. 



The ordinary cries of the Common Tern are a harsh, 

 short ki^), and a continual tee, tee, tee, which breaks, when 

 the bird is excited, into a harsh tee'-arr ; no one who has 

 ever set foot on an island colonized by terns will ever for- 

 get the ear-splitting din made by thousands of angry birds 

 uttering this cry. Terns may easily be distinguished from 

 gulls by the long forked tail ; in adults, moreover, the 

 whole top of the head is black. When feeding, terns hover 

 at some distance above the water, with bill pointing down- 

 ward, and seize their prey by a quick downward plunge, 

 which carries them often well under water. Their flight is 

 more buoyant than a gull's ; each stroke of the long, narrow 

 wrings lifts them easily upward. When not feeding, they 

 gather in large flocks on some exposed sand-spit, but are 

 restless, and often rise, wheel about, and settle again, for no 

 apparent reason. They also light on spindles, spars, and any 

 available perch, and often on the water. W^hen seen near 

 at hand, the red bill with its black tip is conspicuous, and 

 distinguishes the Common Tern from the Arctic and Roseate 

 terns. Young birds and old birds in the fall have whitish 

 foreheads. (See the two preceding species.) 



Caspian Tern. Sterna caspia 



21.00 



Ad. — Top of head black; back and wings pearl-gray; tail and 

 iMider parts white; hill bright red. 



When a student has learned readily to distinguish a tery 

 from a gull he may hope to identify the Caspian Tern, 

 which is a rare migrant off the coast in August and Sep- 



