198 BRITAIN^S BIRDS AND THEIR NESTS. 



'castings,' They are pure white in colour, and are more 

 nearly round than is the case with most birds ; the two 

 ends are similar, and the length does not greatly exceed 

 the breadth. Both colour and shape are tjj^ical of the 

 Order. The young, too, are typical, and similar to those 

 of the true Birds-of-Prey — helpless at first, but covered 

 with white down. Owls are early nesters, and eggs of 

 this species may often be found in March. The eggs are 

 frequently laid in pairs at intervals of some weeks, the 

 young birds of one set probably supplying most of the 

 heat for the incubation of the next. Young of three 

 ages have been found in one nest. The young in the 

 nest utter a peculiar snoring noise, which is said to be 

 used by the adults also. When a full-grown bird is 

 'cornered' and aroused in the daytime, it emits a 

 hissing sound, snaps the bill violently and loudly, and 

 erects its feathers all over its body. Other kinds behave 

 very similarly. 



'White-Owl' is quite an appropriate name for this 

 bird, for it is typically very much lighter in general tone 

 than the other Owls we have to deal with. As is usual 

 with Owls, there is no plumage variation with either sex 

 or season, and very little with age. As in some other 

 species, however, two ' phases ' occur quite irrespective of 

 these factors. The one most common in the British Isles 

 has the upper -parts predominantly orange -tawny, the 

 facial disc white with a dark rim. The other is much 

 darker altogether, and has buff-tinted under-parts and a 

 chestnut tinge on the face. 



'Luminous Owls' were recently a subject of discussion 

 in the Press, examples showing a sort of phosphorescent 

 light on their plumage being recorded from several 

 districts. Many wild theories as to the origin and 

 possible use of this luminosity were put forward. One 



