346 NATURAL HISTORY OF BIRDS. 



a nocturnal life, it of necessity hunts by daylight during the summer. But as it is 

 essentially a forest bird it keeps in the shadow of the trees as much as possible, and 

 has been observed to be most active when the sun is at its lowest point. Its food is 

 stated to consist largely of hares and smaller mammals, but in Alaska Mr. Dall found 

 it feeding almost entirely on birds. 



The structure and affinities of the singular East Indian Phodilus (or Photodilus) 

 have already been briefly alluded to, and, as we are unable to present any account of 

 its habits, we need only add here that the single species, P. badius, is a native of the 

 eastern parts of India, and has been found in Ceylon, Java, and Borneo. 



The barn-owls (sub-family Aluconinae) form a small group, the members of which 

 resemble each other very closely, while they differ strikingly from all other owls. We 

 have already shown how different is their bony structure, and their superficial appear- 

 ance is equally remarkable. The facial disk here reaches its highest development, but 

 instead of being more or less circular, as in all other owls where it is well developed, 

 it is elongated and almost triangular, giving the face a most remarkable expression, 

 not distantly resembling that of some monkeys. Moreover, the head is much pro- 

 duced in front, the bill being much longer proportionally than in other owls, while the 

 legs are also long and scantily feathered, and the grotesque movements and strange 

 postures which the bird assumes still further increase its singularity of appearance. 

 The type of the sub-family is the European barn- or screech-owl, Aluco flammeus, 

 represented in North America by a slightly different form, the race or sub-species 

 pratincola of most authors. 



The barn-owl has a remarkably wide distribution, its range being greater than that 

 of any other owl. It is not found in New Zealand ; in America it does not ordinarily 

 pass north of latitude 45, and is unknown in Scandinavia, but with these exceptions 

 it probably occurs all over the world. 



Correlated with this extensive range, we find great variability, and many of the 

 more or less permanent 'varieties' or races have long been considered true species. 

 Tims North American birds are almost invariably darker than average European ones ; 

 but a dark phase very like that of the American bird sometimes occurs in Germany 

 or England, while specimens from the West Indies are fully as light colored as the 

 lightest Eui'opean ones, and about equalled in this respect by Australian birds. Not 

 only do the colors vary in kind and intensity, but the pattern of coloration is some- 

 what variable ; some birds being irregularly barred below, others spotted, and still 

 others immaculate white. In most of the races the tail has from four to six dark bars, 

 but Jamaican birds have the tail pure white, and English ones almost so. There is, 

 furthermore, considerable difference in size, and some slight difference in the propor- 

 tions of parts. The smallest birds are pi-obably those of Europe, scarcely exceeded, 

 however, by the South American form, while the North American birds are much larger 

 than the European, and these again are far excelled by those of Java and Australia. 



All these forms and many others were formerly ranked as so many separate species, 

 but out of fifteen or twenty names in general use a score of years ago for forms then 

 considei'ed specifically distinct, all but four or five are now pretty generally admitted 

 to indicate only geographical races, or light and dark phases of the single species, 

 Aluco flammeus. These four or five seem to differ more strongly from the common 

 type than any of the others, but it is noticeable that even here the differences are 

 entirely of degree, and not of kind ; the principal points being depth of color, degree 

 of spotting, and size or shape of spots. 



