The Body of a Bird 



33 



wondered, when I saw mounted specimens in museums, 

 with what special immunity from danger these birds 

 were blessed, their beautiful colouring would seem to be 

 such a startling advertisement of the bird's whereabouts. 

 But in reality the very diversity in hue is their protec- 

 tion, and they merge per- 

 fectly into their environ- 

 ment of green foliage and 

 bright sunlight." 



Indeed absolute uniform- 

 ity of coloration instantly 

 reveals the outline of the 

 bird entire, and renders it 

 very conspicuous. Birds 

 which have but few ene- 

 mies are often thus mono- 

 crome in hue. But look 

 at the photographs and 

 see how a broken colora- 

 tion baffles the eye. If 

 the Sooty Tern, Fig. 238, were totally black, it would 

 be conspicuous even against a patch of dark-coloured 

 mottled shingle. But the transverse lines of white across 

 the back totally destroy the symmetry of form, while 

 the white wing-edges fairly force the eye to call them, 

 not part of a bird sheltering her eggs, but only two among 

 a myriad irregular edges of coral rock! 



Observe closely the seven young Flickers clinging to 

 their natal stump. As the warriors of Jason sprang forth 

 from the ground fully armed, so the very bark, mottled 



FIG. 240. Brown Creeper circling up the 

 trunk of a spruce. 



