Vol. XVII 
1900 
DwicutT, Moult of Quails and Grouse. 165 
x 
Natal Down.—Not seen. 
Juvenal Plumage, acquired by a complete postnatal moult. 
Similar to adult female but grayer and the throat white instead 
of buff. 
First Winter Plumage, acquired by a complete postjuvenal 
moult excepting the two distal primaries. Several specimens 
have doffed most of their juvenal dress, the last of it persisting 
about the chin and neck. One bird (Amer. Mus. No. 47297, 
British Columbia, August 25) retains only the third and fourth 
primaries and some anner secondaries; the first and second of 
the series as usual only partly grown. 
Lirst Nuptial Plumage, assumed probably by a limited prenup- 
tial moult, but not shown by the series examined. 
Second or Adult Winter Plumage, acquired by a complete post- 
nuptial moult. Several British Columbia specimens, taken in 
August, show actual moult at various stages. 
Later plumages and moults are repetitions of earlier ones. 
Centrocercus urophasianus (Somap). SAGE GROUSE. 
The specimens examined were all taken in Wyoming in August, 
September and October and show the same stages of plumage as 
in the other Grouse. A young bird (Am. Mus. No. 64006, 
Wyoming, Aug. 15) is partly in juvenal dress, the first and second 
primaries not grown and the others already renewed by those of 
the winter dress except the third and fourth. An adult male 
(Amer. Mus. No. 64012, Wyoming, Aug. 25) has assumed new 
primaries excepting the distal two which are old and worn, the 
body plumage is partly renewed. An adult 9 (Am. Mus. No. 
64005, Wyoming, Aug. 15) has the four distal primaries old, the 
others new. The usual sequence of plumages and of moults 
undoubtedly takes place. 
In conclusion I would say that as the subject of moult is to 
many a sealed book, I have gone into details and repetitions that 
may appear tedious, chiefly for the purpose of emphasizing the 
fact that moult is systematic no matter how varied the resulting 
plumage may be. Once let this idea be grasped and the most 
complex problems of plumage may be readily solved without 
recourse to theoretical explanations. 
