170 CHAPTERS ON THE NATURAL HISTORY 



U. aclamsii, the Yellow-billed Loon; U. urcticus, Ike Black-throated 

 Loon; U. pacificus, the Pacific Loon; and U. lumme, the Ked- 

 throated loon. They are all markedly handsome birds; that is, 

 the males in breeding plumage are, and although they have 

 habits very much alike in all the species those habits are fre- 

 quently found to be very interesting. Both in America and the 

 Old World loons are widely known as divers — the Great North- 

 ern diver being the name frequently applied to the largest spe- 

 cies that has a black bill (U. imber). As a rule they far exceed 

 the grebes in size, but like them their legs are placed almost at 

 the extreme posterior end of the body, and they have short wings 

 and tails. Unlike the grebes, however, the toes of loons are en- 

 tirely webbed in front, instead of being lobed, and there are a 

 number of other anatomical differences distinguishing the two 

 families. 



All the loons have excellent powers of flight, but they are most 

 at home in the water, in which element they are divers of the ut- 

 most expertness and endurance. On shore their locomotion is of 

 an exceedingly clumsy character, they merely being able to push 

 themselves along on their breasts by means of their legs. As 

 they build their nests on the ground, sometimes as far as thirty 

 or forty yards from the water's edge, of either some lake or 

 marsh, their mode of progression has the effect of making a regu- 

 lar path to and fro from the nest to the water. They generally 

 lay but two eggs, and these have been described in general terms 

 as being of an elongate-ovate form, deep brown or olive color, and 

 somewhat sparsely spotted or speckled over with a darker brown 

 or black spots. Newton says: "The divers live chiefly on fish, 

 and are of eminently marine habit, though invariably resorting 

 for the purpose of breeding to fresh-water lakes, where they lay 

 their two dark-brown eggs on the very brink; but they are not in- 

 frequently found far from the sea, being either driven inland by 

 stress of weather, or exhausted in their migrations." Further on, 

 in speaking of their flight, he observes that it " is strong and they 

 can mount to a great height, whence on occasion they will rush 

 down with a velocity that must be seen to be appreciated, and 

 this sudden descent is accompanied by a noise for which those 

 who have witnessed it will agree in thinking that thunder is too 

 weak an epithet." 



All the loons have a loud and penetrating cry, which in the 

 Great Northern diver is peculiarly harsh, clear, and resonant. 



