THE OWLS. 57 
upon the ground. The eggs are pure white, completely oval, suboval or 
elongate, in shape, and are usually from two to five or seven in number; 
some Owls, however, after good feeding, when small mammals are abundant, 
become more prolific, and lay ten, or even twelve or thirteen eggs. The eggs 
are usually laid at intervals, and the warm down of the Owlets first hatched 
assists in incubating the later eggs. It thus happens that in the same nest 
Owlets of different age and progress towards maturity will be discovered, to- 
gether with freshly laid eggs. The nestlings are at first covered with a white 
or greyish down. 
The Owls are dispersed over all parts of the world; about two hundred 
species are now known and described. They vary in size from the tiny 
Sparrow-Owls (Glaucidium/, no larger than a Finch, to the fine Eagle-Owls 
(Bubo), which are over two feet in length. Many of the Owls are found in 
two forms of plumage, a grey form, in the northern and north-eastern parts 
of the world, and: a red form, in the west and south. Their classification is 
a matter of difficulty to systematists; the ten Owls upon the British list, com- 
prising four residents and six occasional visitors, are ranked in nine genera! 
Ornithologists, as yet, appear to be unable to decide upon the features which 
offer the best basis for arrangement, the ear (a most important organ with the 
Owls), the skeleton, or the feathers. 
In general, the nocturnal Owls possess the most rounded heads with the 
largest ears, and these are further provided with an operculum, or lid, con- 
sisting of a fold of skin edged with short feathers, and moved by voluntary 
muscles, serving both to protect the large orifice of the ear, and to form a 
conch for the reception of all the undulations of sound. The nocturnal Owls 
hunt for their prey with equal assistance from the senses of sight and hearing; 
in the diurnal Owls, inhabiters of high latitudes, the orifice of the ear is 
smaller, and is without an operculum; these Owls chiefly depend upon their 
powers of vision to discover their prey. Some of the Owls have upright tufts 
of feathers on their heads, which are variously called horns, or ears, but they 
are in nowise connected with the organs of hearing. 
The Owls are a very interesting and useful family of birds, deserving to 
be both valued and protected for the services they render to the agriculturist ; 
they can be easily kept in confinement, and the smaller kinds become amusing 
pets; they are always in excellent plumage, provided they are properly fed; 
their food should never be without something in the nature of feather or fur; 
like all other raptorial birds Owls void the undigested portions of their food 
in the form of elongated pellets, and this they cannot well do without the 
Vou. III K 
