264 Dwight, Plumages of Gulls. [^pril 



the partial prenuptial or spring moult resemble very closely the 

 second-year birds that have not as yet begun this moult. 



2. Pattern of primaries and rectrices. — Next to shape, the pat- 

 terns that mark the quill-feathers of the wings and tail are of im- 

 portance. Every species has a definite adult wing pattern, which, 

 except in the smaller species, is not even foreshadowed in first, and 

 only occasionally indicated in second-year plumages. The same 

 thing is true of the tails. The juvenal or first year primaries in 

 the larger and medium-sized Gulls are as a rule uniformly dingy 

 or black and the second-year primaries that come at the first 

 postnuptial moult scarcely differ although the medium-sized 

 species may have faint indications of "wedges" of a lighter shade 

 on the inner primaries, obscure apical spots or perhaps a dingy 

 "mirror" on the distal quill. The small Gulls during the first 

 year are marked by primaries with more or less dusky areas, but 

 the adult pattern is usually indicated. After the first postnuptial 

 moult then, the new primaries of small Gulls are of adult pattern, 

 those of the larger sized Gulls have a slight suggestion of adult 

 pattern, while those of the largest Gulls at this period hardly differ 

 from the first year primaries. The " wedges " develop sooner than 

 the apical and other spots and the distal primary is the slowest 

 of them all in acquiring adult characters. 



Tails develop a little faster than do primaries, but in the largest 

 Gulls three moults are required and often four before all traces of 

 immaturity disappear leaving the tail either pure white or banded 

 as it is in the adults of some foreign species. 



3. Color and pattern of body plumage. — Under this heading may 

 be included all of the plumage except the remiges and rectrices, 

 and while there is the greatest divergence between the various 

 consecutive plumages, the advance towards maturity in most of 

 the species may be traced through the gradual elimination of the 

 dusky feathers of youth. As the body plumage undergoes two 

 moults each year, the advance is rapid, but at the early moults 

 some brown or dusky feathers are acquired that differ little if any 

 from those that precede them and these immature feathers are 

 often a ready clue to age. The moults of young birds are pro- 

 tracted and the postjuvenal overlaps the prenuptial. Small Gulls 

 at the postjuvenal moult in the autumn acquire a considerable 



