Vol. XVII 
1900 
Dwicut, Moult of Quatls and Grouse. 49 
July 3) is much farther advanced, the chin being clothed, the 
- under wing-coverts replacing the down, the dusky chestnut crest 
appearing, and the renewal of the remiges by the postjuvenal 
moult has involved the sixth to the fifteenth of the remiges. 
first Winter Plumage, acquired by a complete postjuvenal 
moult, excepting the two distal primaries. Young birds are now 
scarcely distinguishable from adults, the colors, however, are not 
so deep. 
First Nuptial Plumage, acquired by a partial prenuptial moult, 
limited to the fore parts of the head and throat. Several Cali- 
fornia specimens, male and female, illustrate this (Am. Mus. 
NOmOtOss, 4. May 7.) No. 61055, 0, May.9,,. No; Grose, 
May 20, and No. 61059, 2, May 23). 
Later plumages are only repetitions of winter and summer 
dress. 
Callipepla gambeli (Gamde/). GamBeL’s PARTRIDGE. 
A fine series of about 150 specimens examined illustrates all 
the plumages and moults of this species. 
Natal Down. — Very similar to Cal/ipepla californica. Above, 
the crown is pale brown bordered by pale buff lateral stripes, the 
back nearly black and a dusky line behind the eye. Below, dull 
white, sides of head and an indistinct collar buff. A chick 
(Amer. Mus. No. 51426, Arizona, June 6) shows eight of the ten 
primaries just breaking from their follicles, most of the second- 
aries being at a similar stage of development. 
Juvenal Plumage, acquired by a complete postnatal moult. 
Until the plumage of the nape appears the birds are almost indis- 
tinguishable from Cadlipepla californica. - This region is then 
uniformly gray with more distinct shaft-streaks and no dusky 
borders as in californica. A number of specimens show different 
stages of this plumage. Two especially (Amer. Mus. No. 29619, 
g, Arizona, July 9, and No. 51413, @, July 12) show the juvenal 
plumage well advanced and the postjuvenal moult, beginning with 
the tenth primary before the first and second are nearly grown. 
First Winter Plumage, acquired by a complete postjuvenal 
moult, excepting the two distal primaries. Young and old become 
4 
