IO2 



The Loons and Grebes 



with sidelong glance, then peering into the depths below, sought for some 

 attractive morsel. In an instant, with the peculiar motion, impossible to de- 

 scribe, they would disappear beneath the surface, leaving a little foam and 

 bubbles to mark where they went down, and I could follow their course under 

 water; see them shoot with marvelous swiftness through the liquid element, as, 

 urged by the powerful strokes of the webbed feet and beats of the half -opened 

 wings, they flew rather than swam ; see them dart out the arrow-like bill, transfix 

 an unlucky fish, and lightly rise to the surface again." 



The characters upon which the species of Loon are based, although not very 

 striking, are ordinarily sufficient for their ready identification. Thus the first 

 four species to be mentioned agree in having the tarsus shorter than the middle 



FIG. 31. Common Loon, Gavia imber. 



toe without the claw, and in having the fore neck blackish in summer. In the 

 so-called Common Loon (G. imber} the bill in the mature bird is blackish and 

 the head and neck are glossed with velvety green; the length "is from twenty- 

 eight to thirty-six inches. This bird is found throughout the northern part of 

 the Northern Hemisphere. Its closest relative is the Yellow-billed Loon (G. 

 adamsii], so named from the fact that the bill is almost wholly yellowish white, 

 while the head and neck are glossed with velvety violet-blue. It is also the 

 largest species, ranging from thirty-five to thirty-eight inches in length, and in- 

 habits western Arctic America and northeastern Asia. These two species have 

 the head and neck black all around, while in the two following these parts are 

 grayish. Of these the Black-throated Loon (G. arctica) is so called from the 

 blackish fore neck, this being glossed with velvety purple. It is smaller than 

 either of those above mentioned, being from twenty-six to twenty-nine inches 

 long. It ranges over the northern portions of the Northern Hemisphere, breed- 



