42 BIRD BEHAVIOUR 



* 



head, as is so often seen to be done in the feeding 

 of long-billed birds. At the same time, so that the 

 bird can keep a look about it when its bill is driven 

 into the soil, the eyes are situated far back in the 

 head, reminding one of the similar shifting back of 

 the eyes in the most highly developed grazing 

 beasts, such as horses and cattle, though here the 

 necessity for deep-rooting molars is given as the 

 reason. 



Structure and function correspond very closely in 

 the Snipe group ; for instance, the Common Snipe 

 (Scolofax gallinago) and its East Asiatic ally the 

 Pintail Snipe (S. stenura), which are exceedingly 

 alike in size and plumage — -the curious narrow 

 feathers in the tail of the latter not being noticeable 

 till looked for — can be quite easily separated by 

 the difference in the bill, expanded at the tip in 

 the common species, and of uniform calibre in the 

 Pintail ; and their habits correspond, the Common 

 Snipe being mainly a mud-feeder and worm- 

 catcher, while the other often feeds on dry ground 

 and has a more varied menu, including land-insects 

 and l^ad-shells to a great extent. Through the 

 Sandpipers of different sorts a gradation can be 

 traced from these specialized bills to the short 

 pigeon-like ones of the Plovers, with their normally 

 placed eyes. Yet these are also worm-eaters and 

 borers to some extent, so that here, as in the case 

 of the Duck tribe, we can trace the evolution of 

 structure and habit most satisfactorily. 



Two or three interesting little off-shoots of this 



