I ONGEARED, SHORTEARED, AND TAWNY-OWLS 411 



that is to sa\. thrx pr, -x, - M i Imili :i ji.\ and a red phase of plumage 

 <l> :ts^>). Imt it will probably In- found that i\i\^ red, or "hepatic," 

 phase ix ivt.iiiird ilin.u_'lioiit Mi' though this is not true of the cuckoo, 

 which presents a similar dimorphism. The female in always inclined 

 to rufous: indeed, tin- ta\vny-ow|s of this country are markedly more 

 rufous than those of the Continent, even those of the "grey" phase. 



Like tin- rest of its genus, the tawny-owl has unusually large eyes, 

 in consonance with its more strictly nocturnal habits; and, further, 

 tin iris is of an extremely dark brown, HO that the eyes are commonly 

 described as black, and in this coloration the tawny agrees with the 

 burn-owl, and the rim of the eyelid has a curious pink colour, adding 

 a curious effect to the bird's appearance. But in the majority of owls 

 the iris is yellow, generally of a rich golden yellow, and it would 

 seem that in cases where the iris is of this bright hue the birds are 

 IMS strictly nocturnal This connection between the colour of the 

 iris and nocturnal habits cannot, however, be pushed very far, for the 

 barn-owl will hunt by daylight : and we get a similar diversity in the 

 colour of the iris among the Accipttres, which are all diurnal, since 

 the falcons and eagles, for example, have a brown iris, while most 

 of the other AccipUres have a yellow iris. Another peculiarity of the 

 o\\ls so far described is the fact that the outermost quills have the 

 outer webs curiously serrated ; whether this in any way contributes 

 towards the silent flight is doubtful Finally, we come to the most 

 remarkable of all the external character of these owls to wit, the 

 structure of the external ear, which presents certain puzzling features 

 which neither the anatomist nor the field ornithologist has suc- 

 ceeded in interpreting ; indeed, the riddle seems insoluble, though it 

 may prove to be associated with the extremely acute sense of hearing 

 which these birds seem to possess. Briefly, in many owls, .</. 

 Speotyto, the external aperture of the ear differs in no wise from that 

 obtaining in other orders of birds that is to say, it presents a simple 

 round hole guarded by stiffened feathers with few barbs. In the eagle- 

 owls and Scops this aperture is conspicuously enlarged. But in the 



VOL. n. :< (. 



