612 



BRITISH BIRDS. 



the Utopian system of priority, which still further complicates the sub- 

 ject. No better instance could be adduced of the greater generic value, in 

 some cases, of colour than of structure. The emerald-green on the head 

 and some other peculiarities of coloration have survived great changes in 

 the form of the bill. 



The Eider Ducks fly, swim, and dive with great ease, but their short 

 tarsi cause them to walk very badly. They are exclusively coast-birds, 

 and almost exclusively feed upon insects, shell-fish, or other animal food. 

 Their notes are very harsh. They breed on the ground. 



