14 LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS 



in the collection of Dr. Jonathan Dwight, in nearly full nuptial 

 plumage, collected November 25, but I can only regard this as an 

 exceptional case of retarded or suspended molt. A partial prenup- 

 tial molt occurs early in the spring involving mainly the plumage 

 of the head and neck and producing the clearly denned black crown, 

 gray cheeks, chin and throat and the brilliant red neck and breast of 

 the nuptial plumage. I have seen specimens in which this moult was 

 complete before the end of February "and others in full winter 

 plumage in March; I think the moult usually occurs in April. 



Food. Holboell's grebe feeds to some extent on small fish or min- 

 nows which it obtains by diving, but its food consists largely of other 

 things and it can live perfectly well in lakes where there are no fish 

 at all. In the lakes of Manitoba it lives largely on crawfish, ambly- 

 stomae, and aquatic insects; its bill of fare also includes various 

 aquatic worms, insects, and their larvae, small crustaceans, fresh 

 water mollusks, tadpoles, and some vegetable substances. An adult 

 bird caught on the ice near my home was fed on small live shiners 

 which it ate readily. Mr. Robert J. Sim (1904), who made a care- 

 ful study of a captive HolbcelPs grebe, gives the following account 

 of its feeding habits: 



On the second day I placed a 4-inch wild fish (shiner?) in a dish filled with 

 water. This was set on the floor in front of the bird. He gave the fish a slight 

 poke whereupon it swam around violently. Making a quick thrust he caught 

 it, grasping it crosswise with the bill not impaling it. The fish then went 

 through a course of pinching from head to tail, being hitched along from side 

 to side in the bill. It was then turned about and gulped down head first. Later 

 in the day three out of four strips of raw whitefish were eaten, each about the 

 size of a man's finger. These the grebe bruised and shook until small fragments 

 flew several feet around. At this time of the year live food was scarce, but 

 we succeeded in finding a few small aquatic animals. By the 27th of February 

 the grebe had eaten all voluntarily the following: 10 live goldfish (2 to 5 

 inches long), 2 pieces raw steak (taken from water), 1 4-inch wild fish, 2 large 

 tadpoles, and 7 medium sized dragon-fly larvae. 



In swallowing the large goldfishes the bird's jaws seemed to be distended 

 laterally, and he gulped so violently that the back of his head struck his back 

 with a hollow "tunking" sound. This operation apparently jarred the fish 

 past the sticking point. When very hungry the grebe swallowed the fishes alive. 

 Of the crawfishes offered him only the small or soft ones were eaten, and no 

 great relish was shown. Earthworms, when their season came, were eaten 

 with avidity, but raw beefsteak (lean) was the principal article of diet with 

 the bird during his stay with us. 



The stomach of this bird is sometimes wholly or partially filled 

 with feathers. 



Behavior. In flight Holboell's grebe is easily recognized in any 

 plumage; its size is distinctive, being halfway between a loon and 

 one of the smaller grebes; in the full nuptial plumage the red neck 

 and gray cheeks are conspicuous if the bird is near enough to see 



