54 DwiciHT, Moults and Plumages of Gulls and Ter7is. [^^"J' 



Sterna hirundo IJnn. Common Tern. 



1 . ATatal Doum. — This covers the chicks thickly and is yellow- 

 ish with black spots or mottling above and a dusky area on the 

 chin and sides of the throat. 



2. Juvenal Plumage acquired by a complete postnatal moult 

 shortly after leaving the egg. Dusky markings and buff edgings 

 are conspicuous above, the lower parts being a clear white. The 

 forehead is pale brown blending into a dull black occiput. Buffs 

 and browns later become dull white by fading and the blacks be- 

 come brownish. The forking of the tail is much less than that of 

 adults and the rectrices are more rounded, darker and tipped with 

 dusky or buff markings, which become largely lost by wear. A 

 couple of rows of lesser coverts along the cubital border of the 

 wing form a dull black band. The flesh-colored bill and feet, after 

 first brightening, begin to darken. 



In Nova Scotia young birds are on the wing before the first of 

 August but often not till considerably later, and the birds of the 

 Virginia coast do not seem to be very much earlier. The misfor- 

 tunes to eggs and broods must be held responsible for the extreme 

 variations in the times of moult of this as well as other species of 

 terns. Some, if not all terns, young as well as adults, migrate 

 southward before beginning to moult, as is proved by specimens 

 taken in juvenal and nuptial dress far south of their breeding 

 grounds. 



3. First Wititer Plumage acquired by a partial postjuvenal 

 moult, limited to the body feathers, and sometimes a few of the 

 lesser wing-coverts. The new mantle is gray except for the dusky 

 cubital bands. The forehead is white and the occiput black, with 

 some tendency to streaking on the crown. The bill and feet 

 become wholly black. Save for the less forked, darker tail and 

 traces of buff on the retained wing-coverts, young birds closely 

 resemble adults. The change to this plumage is not apt to begin 

 before the end of September on the Atlantic coast. 



4. First Nuptial Phnnage acquired by a complete first pre- 

 nuptial moult, which explains the freshness of all the feathers 

 of breeding birds. The lateness of this moult in some birds is 

 indicated by over fifty specimens (some of which appear to be 



