306 BIRDS OF NORFOLK. 



Dresser's "Birds of Europe" the following characters 

 by which they may be distinguished from the common 

 tern : — 



1. The tail is much longer, and in the adult bird 



in summer plumage reaches beyond the wings. 

 Hence Naumann's name of macrura. 



2. The tarsus, both in old and young birds, is much 



shorter than in the common tern. 



3. The bill is almost entirely crimson, without any 



black on the culmen ;'* it is also more slender. 



4. Young birds are more difficult to determine ; but 



the tarsus [which is only half an inch in length] 

 is a sure sign of distinction ; and, moreover, 

 there is a less amount of greyish black on the 

 outer primaries. 



The under surface of the body is also as grey, or 

 nearly so, as the back, whereas in the common species 

 it is, as a rule, much lighter or white. 



STERNA HYBRIDA, Pallas. 

 WHISKERED TERN. 



Mr. J. H. Gurney possesses the only Norfolk speci- 

 of this rare tern, which was shot on Hickling Broad, on 

 the 17th of June, 1847, by the late Mr. J. Sayer, of 

 Norwich. Mr. Gurney, in recording its occurrence in 

 the " Zoologist " for 1847, p. 1820, remarks, " It proved 

 to be an adult female, and contained ova in an advanced 

 stage, the largest being apparently almost ready to re- 



* Professor Newton tells me that in Iceland, in the year 1858, 

 in company with Mr. Wolley, he shot from amongst a flock of 

 undonbted arctic terns an over year bird which had the bill black. 

 The conclusion he arrived at was that the bill in this bird for some 

 reason or other had not attained the full colouring, and he thinks 

 it possible that occasionally, though very rarely, such a variety 

 may be met with. 



