NOTES. 289 



re-inspected the photograph and must oun that I decided 

 wrongly. It represents the earHest phase of the up-stroke, 

 not the concluding one of the down-stroke. But I am 

 unable to explain the slight upward curve of the feathers. — 

 F. W. Headley.] 



"LUMINOUS OWLS." 



In the past month we have been confronted at every turn by 

 wonderful stories of a pair of luminous Owls, which apparently 

 possess the power of emitting a light sufficiently brilliant to 

 be mistaken for the light of a bicycle lamp ! 



Sir Digby Pigott first gave publicity to this apparition, and 

 in later communications to the Press made comments thereon 

 which betrayed an unfamiliarity with the nature of the facts 

 he quoted. The most startling of these was his hypothesis 

 that this light was not only normal, but that it is used by the 

 Owls as a kind of policeman's dark-lantern, or as a means of 

 fascinating their victims ! 



Briefly, there are only three possible explanations for the 

 phenomenon he has so vividly described. 



Firstly, and most probably, this luminosity may be due to 

 phosphorescent bacteria derived from decaying wood. These 

 bacteria could easily become rubbed into the feathers by their 

 contact M ith the sides of some hollow tree in which the birds 

 have probably been roosting. But as feathers Mould scarcely 

 afford a nourishing medium for such bacteria, they would 

 speedily lose their vitality. Secondly, it may be due to a 

 s^Decies of feather-fungus new to science, for it is already 

 known that feather-fungi exist ; one species, for example, 

 has been described from the feathers of a Goose. Thirdly, 

 and this is less probable, the light may be due to a diseased 

 condition of the oil gland, whereby the secretion of oil has 

 become excessive, and its properties so changed as to become 

 luminous on exposure to the air. In a word, the phenomenon 

 is abnormal, and the light is almost certainly due to 

 extraneous matter. 



Although the Barn-Owl — the species, according to Sir 

 Digby Pigott, responsible for this strange light — is so useful 

 a bird, this " luminous " example should, in the interests of 

 science, have been secured and submitted to some competent 

 authority for examination. — Eds. 



CHIFFCHAFFS IN SHETLAND. 



With reference to the record of additions since 1899 with 

 regard to the Chiffchaff {Phylloscopus rufus) in Shetland 

 (vide antea, p. 82) I find on referring to my notes that on 



