CHAPTER XVI 



THE LOONS AND GREBES 



(Order Colymbiformes') 



LTHOUGH placed next to the Penguins, the members of the present 

 order are of course quite markedly different from them, but, as sug- 

 gested in the chapter on classification, this disposition illustrates 

 one of the difficulties of a linear arrangement, and it does not follow 

 that all placed contiguously are equally related. However, the Colymbiformes are 

 also a group of ancient origin and likewise hold a somewhat isolated position. 

 They were formerly associated with the Auks, and as a matter of fact they not 

 only show affinities with them, but with several other groups, yet comparatively 

 recent anatomical studies have demonstrated that they are, on the whole, abun- 

 dantly distinct and well entitled to be ranked as a separate order. They are 

 all markedly aquatic birds of medium or large size, with moderately long necks, 

 long, mostly sharp-pointed bills, usually strong wings, and webbed or lobed toes. 

 Perhaps the most marked anatomical features are the laterally flattened meta- 

 tarsi, and the peculiar upward prolongation of the cnemial crest of the tibia. 



The Colymbiformes are divided into two families, the Gavidce, or Loons, and 

 the PodicipedidfB, or Grebes. The first is distinguished by having the hind toe 

 on a level with the other toes, which are united by a web, and by a tail of eighteen 

 or twenty short, stiff feathers. In the Grebes the hind toe is raised above the 

 level of the others, while the toes are provided with wide lateral lobes, and 

 the tail usually so reduced as to be indistinguishable, though, as Pycraft has 

 recently shown, it is never really absent. 



%. 



THE LOONS, OR DIVERS 



(Family Gavida) 



As a family the Loons are relatively very old, two or more fossil representa- 

 tives having been discovered in the lower Miocene of France and the Pliocene 

 of England, but so far as we are able to determine they did not differ essentially 

 from the modern representatives, showing that the latter have changed but little 

 with time. They are birds of large size, ranging between twenty-four and thirty- 

 eight inches in length, and are past masters in the art of swimming and diving. 

 They present a very awkward appearance on land, since the legs are placed 



