^ Ol 1909^ VI ] Townsend, Use of Wings and Feet by Diving Birds. 245 



flippers, — most markedly so in the case of the Penguins, — thereby 

 showing that large wings are not only unnecessary, but even a 

 hindrance in subaqueous flight. In attaining this end they were 

 obliged to sacrifice aerial flight. This the Penguins were able to 

 do owing to the absence of land mammals in their antarctic breeding 

 grounds. The same conditions existed for the Great Auk at its 

 chief breeding place in this country on Funk Island, until the 

 arrival of that most destructive land mammal, the white man. 



The Diving Petrel of the Straits of Magellan is a bird that appears 

 to be in danger of sacrificing aerial for sub-aqueous flight, and 

 illustrates the inconveniences of this line of evolution. Xichol (14) 

 says of this bird, after describing its short flights in the air and its 

 diving: " In appearance it reminds one forcibly of the little auk. . . . 

 The wings are very small and weak, the bird, doubtless, is losing 

 the power of flight." 



In the case of the existing Alcidae and of the other birds that 

 habitually use the wings alone in diving, it would be interesting 

 to determine whether they are able to progress under water as fast 

 as those birds that use the feet alone, for the Alcidae are trying to 

 make the same tool work for two purposes, to propel them in the 

 air as well as in the Avater. One is impressed with the imperfection 

 of their wings for both purposes, when one watches a Puffin en- 

 deavoring to get out of the way of a steamer. First the bird dives 

 and flies under water. Then in alarm it rises to the surface and 

 attempts to ascend into the air on its wings, but unless there is a 

 strong wind to act on its small aeroplanes, it soon gives up the 

 attempt and flops down into the water again. Although it would 

 be difficult to prove, it would seem to me reasonable to suppose 

 that the compressed pointed body of the Loon, with the air ex- 

 pelled from beneath the flattened feathers, would make faster 

 progress by feet action alone, than by the wings or by the wings 

 and feet combined, unless the wings were reduced to the propor- 

 tions of flippers. It is possible that the occasional use of the wings 

 observed in these birds may be explained by fright, which causes 

 them to "lose their heads," and return to the ancestral form of 

 progression, to a reptilian scramble so to speak, without increasing 

 the speed of their progress. It could also be argued that the wings 

 of Loons are now so reduced in size that their use in emergencies 



