A LABRADOR SPRING 



The group of river ducks, on the other hand, 

 which includes the teals, mallard, black duck 

 and wood duck, are not skilled in diving but 

 obtain their food by dipping their heads and 

 necks below the surface, while their tails point 

 to the zenith in the ardour of the pursuit. 

 These birds as well as geese and brant do, 

 however, occasionally dive in an awkward 

 manner, and in so doing use both feet and 

 wings. 



The family of the loons and grebes is a curious 

 one and its members are characterized by 

 possessing very muscular legs, the thighs short 

 and stout, the lower legs long and provided with 

 keels for the attachment of powerful muscles. 

 The grebes have also a very large knee-cap. 

 In these respects 'the group resembles the fossil 

 Hesperornis, a toothed bird with wings repre- 

 sented by mere vestiges, but one that was 

 evidently strongly specialized for propulsion 

 through the water by means of the feet alone. 

 Now loons and grebes are expert divers, and, 

 although they occasionally have been seen to 

 use the wings when hard pressed, as a rule they 

 appear to swim, and that too very rapidly, 

 under water with the feet alone. Young loons, 

 194 



