YELLOW-BILLED LOON 63 



The molt into the winter plumage is very irregular and much pro- 

 longed, and the plumage is worn for only a short time. He refers 

 to a specimen taken on September 22 in which the molt had begun, 

 others taken in October and November in transitional stages, and 

 one taken on October 5 in which the summer plumage was almost 

 entirely retained. A specimen taken on January 11 "still retains 

 a number of white-spotted summer feathers on its back and shoul- 

 ders," and one taken at the beginning of May shows molt into the 

 summer plumage. The two molts are so prolonged and so irregular 

 that they may almost be said to overlap. 



Dr. Witmer Stone ( 1900) describes an adult winter bird as follows: 



One adult specimen, September 29, has just completed the molt, and the new 

 wings are only half grown; above glossy black with a tinge of green appearing 

 "scaly" in certain lights, top of head and back of neck black, feathers on sides 

 of neck slightly tipped with black. The flight feathers in the loons are evi- 

 dently lost all at once, as in the ducks. 



Behavior. Professor Collett (1894) says of the habits of the 

 yellow-billed loon: "But little information has been obtained on 

 the Norwegian coasts. Some of the specimens were caught in nets 

 in which they had been entangled when diving." One "was taken 

 on a hook which was laid at a depth of about 15 fathoms." In the 

 specimens that he dissected the stomachs were "filled with the re- 

 mains of fishes, and had a quantity of gravel in" them. "The last 

 specimen received contained an example of Cottus scorpius [total 

 length 270 mm., a full grown female with roe]." 



Mr. Joseph Dixon (1916) refers to the flight of this species as 

 follows : 



The flight of the yellow-billed loon in migration was one of the most im- 

 pressive sights of our Arctic trip. A dim speck low over the frozen tundra or 

 glaring ice fields suddenly develops wings which beat rapidly with the rhythm 

 and energy of a steam engine. The huge bill and neck seem to be extended 

 slightly upward and the bird glides swiftly forward in a straight line with 

 none of the undulating movements of the brant and eider ducks. The rapid 

 "swish, swish," of the huge wings dies away in the Arctic silence, and the 

 next moment one is gazing in the distance where a rapidly diminishing dark 

 object seems to be boring a hole in the low clouds in the east. There was no 

 variation in speed or direction, and the birds traveled at least 40 miles an 

 hour over a measured distance. 



Mr. Murdoch (1885) writes: 



They are generally to be seen alone or in pairs, seldom more than three or 

 four together, and are silent birds compared with C. torquatus. I only heard 

 this bird "laugh" once during the whole of my stay. The "laugh" appeared 

 to be harsher than that of torquatus. 



Mr. F. Seymour Hersey, in his field notes, describes the call of this 

 species as "a wild, ringing laugh, similar in many respects to that of 

 the common loon, but louder." 



