Jones — On Common and Roseate Terns. 45 



The young in his first definitive feather plumage is, in 

 hirnndo, barred across the back and wings with dusky brown 

 and rufous. The main body of the feather is "gull blue," its 

 distal end is rufous-brown for the space of several millimeters 

 in width, and between this rufous brown distal margin and the 

 field of "gull blue" there is a crescent of black which is very 



Figure 4 



Common Tern {Sterna liirundo). Downy young, three 

 days old. 



variable in extent. Enough of the feather is exposed to show 

 the three colors mentioned above. The combined effect is a 

 distinct barring of the color pattern of the upper parts. The 

 entire under parts are pure white. In doiigalli the pattern is 

 more varied and is well illustrated by figure 1. Here the 

 black tends to form more than one bar. 



