Lake Maxinkuckee, Physical and Biological Survey 505 



coots. At these times they present an interesting and attractive 

 sight. The play of colors when the sunshine glints on the purple- 

 black heads of the males as they bob up and down on the passing 

 waves, makes them conspicuous objects easily recognizable from 

 other ducks. In stormy weather, or when disturbed, they move 

 farther out on the lake or seek the quiet protected places. When 

 far out on the lake they often appear as a long black line. At 

 night, especially in foggy weather, they frequently come ashore. 



Sometimes they remain in winter even after the lake is frozen 

 entirely over. This was the case in 1904 when the lake froze sud- 

 denly. Then these ducks were seen in considerable numbers walk- 

 ing about on the ice. 



Six examples of this duck that were weighed and measured gave 

 the following data: 



A good many stomachs of Little Bluebills were examined. The 

 results of these examinations and our observations lead us to the 

 conclusion that their food consists chiefly of small mollusks (prin- 

 cipally Vivipara contectoides at this lake) and vegetation. The 

 stomach of one shot December 1, 1904, contained about 1,000 very 

 small shells, probably the young of Vi\'ipara. While the wild cel- 

 ery lasts they feed largely on it; later they will eat bits of Pota- 

 mogeton leaves, Chara and even Myriophyllum and Ceratophyllum. 

 We have no evidence that they ever feed on fish. 



The Little Bluebill does not rank with the redhead and the 

 canvasback as an article of food. However, during the early part 

 of the fall when it is feeding on the wild celery, it is quite delicious. 



28. RING-NECKED DUCK 



MARILA COLLARIS (Donovan) 



This little duck, known variously as Ring-billed Blackhead, 

 Marsh Bluebill, Ringbill, and Ring-necked Scaup Duck, appears to 

 be rare at Maxinkuckee. The difficulty of distinguishing it cer- 



