250 NYROCA MARILA 



the latter often containing a few vermiculated feathers. Back, rump, upper tail-coverts and tail very 

 dark brown. Upper breast brownish, fading into the white of the lower breast and upper abdomen. 

 Lower abdomen and under tail-coverts more or less brownish. Outer wing-coverts uniform like the 

 mantle. Remainder of wing nearly as in male. A very old female (Museum of Comparative Zoology) 

 formerly in a collection of live water-fowl, is beginning to assume male plumage and has the head 

 black, while the white face-patch is still present. There are black feathers coming in on the breast. 



Iris yellow. Bill as in male but not so brilliant. Legs and feet as in male but duller. 



Wing 202-220 mm.; bill 41-46; tarsus 40. 



Weight 2 pounds to 2 pounds, 5 ounces (0.90 to 1.0 kilogram) average of adults in North Carolina 

 in December 2 pounds, 2 ounces. 



Note: This sex cannot be distinguished from the female of the Lesser Scaup except by the larger 

 measurements of bill and wing. 



Female in First (Juvenal) Plumage: Very like the adult female, but the white face-patches are 

 much more obscure and at first are scarcely to be seen. The forehead is nearly always brown. The 

 scapulars do not at first show any vermiculation and the lower abdomen is apt to be brown, while the 

 tail-feathers are faded and worn at the tips. These immature females can be told at a glance from 

 American Red-heads or European Pochards in similar plumage by their white speculum-patches. 

 They can be distinguished from the females of the Ring-necked Scaup (Nyroca collaris) by the same 

 character. They have a very close resemblance to the female of the Ferruginous Duck (Nyroca 

 nyroca) but are much larger. They are extremely close to the Australian Scaup (Nyroca australis) 

 in similar plumage, but have the whole bill bluish instead of blue only at the tip. 



Young Male in First (Juvenal) Plumage: At first very much like the female but the scapulars 

 show a considerable amount of vermiculation long before such feathers appear in the young female. 

 There is a patch of white along the base of the culmen but the forehead and chin are brown. The 

 occipital region and also the sides of the head are usually darker than in the young female. 



Immature Male: By early October a few black feathers usually appear along the sides of the head, 

 and finally the white face-patch is completely obscured. Later on a few black feathers begin to appear 

 on the upper breast or the mantle and progression to adult stage is gradual. As in other ducks, how- 

 ever, changes to maturity are far from being regular and males in very immature stages may be 

 found in November and December or even later. 



Male in Eclipse: No plumage at all resembling that of the female is apparently ever assumed. Two 

 old males which I took in Massachusetts in early August correspond exactly to the description given 

 by Millais for males in eclipse. The head is dirty-brown to black, except for an indication of white on 

 the area next to the culmen and with more or less grayish brown on the cheeks. There is a distinct 

 light-colored brownish collar. The mantle is not solid black but filled with new vermiculated black- 

 and-white feathers. The scapular region is filled with new feathers that are very much but not exactly 

 like the old ones. Millais thinks that there is no intermediate or eclipse dress here, but a direct change 

 from winter plumage. This I think is open to doubt. The breast is black, each feather narrowly tipped 

 with white, and the lower breast merges into a brownish mottled area, which gives way to the white 

 of the abdomen. The flanks are vermiculated brown and white. I do not believe that there is a direct 

 moult from winter to winter plumage on the breast, such as Millais has described. The black breast- 

 feathers of the eclipse plumage are not exactly like the feathers of the mature plumage and often have 

 concealed vermiculations. The most perfect eclipse specimens are probably to be found in early Sep- 

 tember, as with the Lesser Scaup. I have reason to think that at this time there are no black feathers 



