322 NATURAL HISTORY OF BIRDS. 



The nostrils are of moderate or large size, and open in or near the anterior margin 

 of the cere, being usually hidden by the bristles. 



The legs are much longer than they appear to be, yet never very long. They are 

 always feathered to or below the tibio-tarsal joint, and a really naked tarsus, i. e. Avith- 

 out feathers or bristles, is rarely seen, while even the toes are often well feathered. The 

 fact that the outer toe is reversible has already been noted, and although the presence 

 of a similar structure in the osprey (Pandioii) is probably to be regarded more as a 

 coincidence than as evidence of true affinity, yet it is interesting to notice that the 

 claws are very similar in the two cases. It will be remembered that in the osprey the 

 talons are rounded, not grooved, beneath, and that they are of equal length on all the 

 toes ; while in most if not all other FalconidaB the hind claw is usually largest, nearly 

 equalled by the inner, and the middle and outer are respectively smaller and smallest. 

 The owls most nearly resemble the osprey in these respects, for, although the claws 

 are not smooth and rounded beneath, neither are they furrowed, but ridged ; and very 

 often all are of precisely the same size. Even when unequal, the middle claw is usu- 

 ally largest, being nearly equalled by the inner, while either the hind claw or the outer 

 may be the smallest, though usually they are about equal. 



The wings and tail are generally ample and rounded, the former always more or 

 less concave, the latter often, but not always, short. The plumage is very soft, loose, 

 and fluffy, giving a very false impression of size. Almost all the feathers are soft- 

 fringed, and this is noticeable in the large flight feathers, especially on the outer webs 

 of the primaries, where the fringe is stiff er than elsewhere, and the filaments more or 

 less recurved, all combining to make the flight noiseless as possible. All the feathers 

 are destitute of aftershafts, and the oil-gland lacks the usual circlet of plumes. A 

 great many species show tufts of lengthened feathers on the head, one over each eye, 

 usually called ' horns ' or ' ears ' though a better word is that suggested by Dr. Coues, 

 who calls them plumicorns or feather-horns. It is almost needless to say that they 

 have nothing whatever to do with the ears, and, as they are not peculiar to either sex, 

 they probably serve no purpose as ornaments. They may be depressed or erected at 

 the pleasure of the bird, but in many species are so large as always to be quite con- 

 spicuous. They increase the somewhat striking resemblance which the face of an owl 

 bears to that of a cat, but what useful purpose they serve, if any, is apparently un- 

 known. They occur in widely different genera, and differ much in size and form, but 

 seem to be of little value, except in artificial classifications, representing perhaps the occi- 

 pital crests so frequently met with among Falconidse, but entirely wanting among owls. 



We have spoken of owls as the nocturnal birds of prey, and so most of them are ; 

 yet there is much difference among them as to the power of sight in the night-time, 

 and the corresponding partial blindness by daylight. Not a few of them are entirely 

 helpless in open sun-light, and if discovered under such circumstances may be easily 

 caught in the hand. Others see perfectly well in the light, and even prefer to hunt by 

 day in cloudy or foggy weather. 



This is especially true of such species as the snowy-owl and hawk-owl, which inhabit 

 the far north, where the summer is one long day, or at best there are but one or two 

 hours of twilight in the course of the twenty-four. Probably the great majority of 

 species prefer the twilight of morning and evening, or the semi-darkness of more or 

 less moonlight nights. The structure of their eyes renders them very near sighted, and 

 it seems very probable that many of them are able to hear a mouse much farther than 

 they could see him, though there is a wide difference in this respect in different species. 



