OWLS. 395 



white, and vary from two to five. The young, which are at 

 first covered W'ith greyish, brownish, or whitish down, remain 

 long in the nest, and after going abroad are aided for some days 

 by their parents. When fledged, they generally differ very 

 little in colour from the old birds ; the older the individual is, 

 the more simple is its colouring, the dark markings gradually 

 diminishing in extent, and the tints becoming lighter. 



The moult, which is very gradual, commences in summer, 

 and is completed by the end of autumn. The plumage, owing 

 to its delicate texture and great elasticity, suffers little from 

 friction, and its colours are generally little acted on by the wea- 

 ther. The males are always smaller than the females ; but 

 the sexes seldom differ in colour. 



Some species are in a great measure diurnal, and in aspect 

 as well as manners approach the Falconine birds. They have 

 the plumage somewhat more compact, and the aperture of the 

 ear smaller. The form of their cranium also is very similar to 

 that of the diurnal Raptores. The larger the conch of the ear, 

 and the more downy the plumage, the more strictly nocturnal 

 are the habits. Hence, in arranging the Owls into genera, it 

 is of importance to attend particularly to the organ of hearing. 



Various arrangements, exhibiting various degrees of inge- 

 nuity, have been proposed. All that I have seen are very de- 

 fective ; and I have not yet acquired sufficient knowledge 

 of the subject to frame a satisfactory classification, having 

 dissected only about fifteen species, and examined the skins of 

 about double that number. I shall therefore discard criticism 

 on the present occasion, relinquish the hope of excelling my 

 predecessors, and confine my efforts to the construction of such 

 an arrangement of the British Owls as may enable the student 

 readily to distinguish their species and genera. Let us in the 

 first place attend to the ear. 



In birds generally, and in the Peregrine Falcon in particu- 

 lar, taking it merely as a convenient example, the external ear, 

 Fig. 237, «, is of a roundish form, and of moderate size. It pre- 

 sents a circular thickened margin of skin, a little raised above 

 the surrounding parts, and having its outer edge beset with slen- 

 der feathers, of which the anterior are recurved, much longer 



