BRITAIN'S BIRDS AND THEIR NESTS. 199 



of the few rational explanations is that the light was 

 due to phosphorescent bacteria from decaying wood having 

 been fortuitously transferred to the Owl's plumage. 



THE TAWNY OR BROWN OWL 



(Syrnium aluco). 



Plate 61. 



The Tawny, Brown, or Wood Owl, as it is variously 

 called, is slightly the largest of our native Owls, and 

 represents a somewhat different branch of the Order from 

 that to which the Barn-Owl belongs. But the subdivision 

 of the Owls is a difficult question, and the differences 

 between the minor groups are not of a kind that concerns 

 the general reader. The most noticeable difference between 

 the two birds is in their plumage, the Tawny OwPs being 

 of the mottled brown type which is more characteristic of 

 the Order. In it there are also two 'phases,' one with a 

 rufous and one with a grayish tendency, the former being 

 the predominant variety in our islands. Under natural 

 conditions, however. Owls are more often heard than 

 seen, and the difference between the cry of the two 

 species is perhaps the most generally useful means of 

 identification. Where the Barn-Owl screams, the Brown 

 Owl hoots — 'Tu whit, tu who,' as Shakespeare syllabled 

 the well-known note. Under the influence of a woodland 

 night the timid or superstitious may perhaps find some- 

 thing to fear or dislike in the Brown Owl's 'hoot,' but 

 to the less imaginative wayfarer it often seems a rather 

 merry note. A common form of the cry is a rapid 

 succession of short 'hoots' slurred together, producing 

 a slightly eerie, shivering cry, which has been aptly 

 compared to the bubbling sound made by blowing into 



