Vol. xxxiin 



1916 



] 'Dix.o's, Migration of the Yellow-hilled Loon. oi 6 



to occur, so it seems to me that nothing short of the capture of the 

 parent bird together with the set of eggs, by some responsible 

 party, would constitute a dependable record. 



There is another point also in this connection that may, perhaps, 

 be emphasized here, and that is that the occurrence of many indi- 

 viduals in a region during the nesting season does not necessarily 

 prove that the species breeds commonly there. During the spring 

 of 1907, in the Sitkan district of southeastern Alaska, we found 

 Northern Bald Eagles in abundance, as many as twenty birds being 

 in sight at one time. Over two-thirds of these birds were adults, 

 yet I was able to find only one pair of birds breeding, although 

 man^' old, uninhabited nests were investigated. At St. Lawrence 

 Island in Bering Sea, on June 25, 1913, Emperor Geese were found 

 to be ver\' numerous. Flocks of from seven to twenty were ob- 

 served flying over the large lagoon on the south side of the island. 

 We saw over one hundred birds, but none of those dissected showed 

 signs of breeding, and no recent nests could be found. Along the 

 whole coast of Alaska non-breeding water birds occur in numbers 

 throughout the summer, in places far outside their breeding ranges. 



Under these conditions it seems evident that something more 

 than identification of a species is necessary to establish its status 

 as a breeder in a locality. 



The flight of the Yellow-billed Loon in migration was one of the 

 most impressive 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 upwards, 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 forty miles an hour over a measured distance. 

 Most of those secured were "through travellers" in full flight, and 

 all were exceedingly fat. I weighed the fat that I clipped oft' of 

 one skin, and found it to be a good two pounds. The bird weighed 

 twelve pounds before skinning. 



