COMMON TEEN 319 



Common Tern. 



Sterna fluviatilis. 



FIG. 107. COMMON TERN. } natural size. 



Bill, legs, and feet orange-red ; entire plumage as in the arctic 

 tern, except the lower parts, which are more nearly pure white. 

 Length, fourteen and a quarter inches. 



So nearly alike are the arctic and common terns that it is hard, 

 well-nigh impossible, in fact, to distinguish them when they are 

 observed flying about in company. In size, manner of flight, 

 language, and general appearance, they are identical. On a close 

 examination the common tern is found to be slightly less slender in 

 build, its under parts dull white instead of pale grey, its beak 

 tipped with black and coral-red, instead of blood-red. It is doubtless 

 owing to their similarity that the two species associate freely 

 together at all times, and are often to be found breeding side by side. 

 But while the arctic tern is most common in the north, from the 

 Shetlands, Orkneys, and Hebrides, to the coast of Northumberland 

 on the one side of the country, and of Lancashire on the other, the 

 common tern is common only on the coasts south of these two 

 points. The nest is a slight depression, sometimes with a little dry 

 grass for lining, placed on the shingle of the beach ; the three eggs 

 are yellowish stone, grey, or olive colour, spotted and blotched with 

 dark brown and grey. 



