284 WOODCOCK AND SNIPE 



turned up and spread fanwise so as to shield the back and head. This 

 being so, the dark-coloured under tail-coverts would have a decidedly 

 protective value : white feathers, like those of the jack-snipe, would be 

 conspicuous when so exposed. Finally, while the flank feathers in the 

 common and great-snipe, as in the woodcock, are barred, in the jack- 

 snipe they are longitudinally striped. What interpretation is to be 

 placed on these differences ? It would seem that the median yellow 

 stripe along the crown is a feature which has been lost but recently, 

 since traces are found to-day in some individuals of the species in an 

 irregular rufous band which is soon lost by abrasion. But what are we 

 to say of those losses and gains ? Are they merely the expression 

 points of variation, of no significance one way or another in the 

 struggle for existence, or are they of selection value, and enabling 

 their possessors to fare the more successfully in that struggle ? What 

 part do these stripes play in the life-history of the common-snipe ? 

 The snipe now under discussion, as we have already remarked, differ 

 conspicuously from the woodcock, and agree among themselves, in 

 the darker coloration of the upper parts, and the conspicuous, long, 

 narrow, yellow stripes along the back; and these differences are 

 almost certainly due to differences of environment. But be this as it 

 may, the behaviour of the woodcock, and of the common-snipe at any 

 rate, when striving to avoid detection is quite different. The wood- 

 cock crouches, the snipe depresses the head and tilts the body up- 

 wards till the tail is almost vertical, so that the yellow lines along the 

 back simulate dead stems of reed and grass. One cannot, of course, 

 suppose that the snipe is conscious of the pattern on its back and of 

 the advantage gained by assuming this posture in moments of danger, 

 but the correlation of the coloration and the bird's behaviour clearly 

 points to some advantage in this particular pattern of the plumage. 

 Nevertheless, it does not follow that this pattern is attuned so nicely 

 to the environment that a little more, or a little less, of one or 

 other of its components would endanger the bird's well-being. 

 Indeed, a comparison of a large series, either of woodcock or Snipe, 



