BIKDS. 



281 



among the Mammalia) is extremely sensitive, so that the 

 expression " as blind as an Owl," has no more sense in it 



FIG. 53, BEAK AND TALONS OF EAGLE. 



than " as blind as a Cat " would have ; they feed upon rats, 

 mice, insects, &c. 



2. ThelNSESSOKES include some that live by catchinginsecta 

 in the air while they fly, as the Swallows (fig. 54) ; these are fur- 

 nished with great powers of flight and rapidity of movement ; 

 others (the Scansores) which climb and hold by the branches 

 of trees, feeding upon nuts and fruit, as the Parrot ; others 

 live upon insects, but seek them in the crevices of old trees 

 and other similar places, as the Woodpeckers (fig. 54) . Some 

 live entirely upon fish (King-fishers), which they catch from 

 the streams on the banks of which they live. This order 

 includes all the singing birds, and by far the greater number 

 of birds of passage ; this propensity to migrate is one of the 

 most wonderful of all the instincts of Birds, the Swallow 



