THE SHOVELER 225 



THE SHOVELER 

 [W. P. PYCRAFT] 



Among the surface-feeding ducks the shoveler must always hold 

 a conspicuous place, not only because of the beauty of the drake's 

 plumage, but also on account of the remarkable form of the beak, 

 which, as an ornithological object-lesson in evolution, is worthy of 

 more attention than it has yet received. In all the Anatidse, as 

 everybody knows, the tongue is thick and fleshy, and provided with a 

 more or less extensive lateral armature of spines, while the inner 

 edges of the beak are beset with horny outgrowths. In the Geese 

 and Swans, and in the fish-eating Ducks, these take the form of serra- 

 tions of considerable size, but in the surface-feeding Ducks they 

 assume a more or less bristle-like character ; and in the shoveler 

 these bristles attain their maximum length, which is considerable, so 

 that they form a sifting apparatus, recalling the baleen of whales. 

 Among birds only the petrels of the genus Prion show a similar 

 development of bristles, and herein we have a most excellent illustra- 

 tion of convergent evolution. So far so good. But why in the 

 shoveler alone among its kind have these lamellae attained so 

 great a length ? The answer which would usually be given begs the 

 question, since it would be to the effect that they must be of 

 importance to the bird's well-being or they would not be there. That 

 they are evidence of a high specialisation, enabling the bird to take 

 advantage of a source of food-supply inaccessible to its neighbours, 

 and thereby their possessor gains an advantage in the struggle for 

 existence. This may indeed be true. But so far as the evidence 

 goes, such an answer is lacking in cogency. And this because, so far 

 as the records of the food and habits of this bird go, they do not show 

 that the shoveler differs materially in his choice of food from the 



