CURRENT LITERATURE 95 



CURRENT LITERATURE. 



The Food of some Wild Birds. In a series of short papers 

 Dr W. E. Collinge continues his records of the food content of the 

 crops of our wild birds. Two of the papers before us deal in a 

 general way with groups of birds. Thus in ihe Journal of the Wild 

 Bird Itivestigatioii Society (March 1920) appears a summary of 

 results illustrating the relation of wild birds to the farmer, in which 

 the unassailable conclusion is reached that " in our avifauna we have 

 a potent factor for good that is of the greatest national importance, 

 especially to the farmer and those who live by the produce of the 

 land"; and in Nature (8th April 1920) an account is given of the 

 relation of sea-birds to fisheries and agriculture, in which the Black- 

 headed Gull is singled out for detailed treatment, but in which the 

 general result is reached that with a few exceptions, such as the 

 Cormorant and Shag, "the food of each species is partly beneficial," 

 and "the total percentage of injuries is less than that of the benefits, 

 and the bulk of the food is of a neutral nature." The remaining 

 papers of the series deal with particular species. Of the food of 

 the Barn Owl (as estimated by percentage volume of stomach-content) 

 85.5 per cent, consists of creatures harmful to man's crops (68.5 per 

 cent. Mice and Voles, 9.5 House-sparrows, Starlings, and Black- 

 birds, and 7.5 injurious insects). The same method of estimation 

 shows that the Kingfisher, judging from nest as well as crop 

 contents, destroys 71.0 per cent, volume of neutral food, 16.0 per 

 cent, beneficial, and only 13.0 per cent, injurious (///. Sporting and 

 Dramatic News, 6th March 1920); while the Nightjar's record of 

 88.0 per cent, injurious insects and 12.0 per cent, neutral insects 

 singles it out as a bird highly beneficial and deserving utmost 

 efforts at protection. It is to be regretted that the investigation 

 involved the death of sixty-two specimens of this most useful bird. 



A Variety of Mollusc new to Scotland Helico^ona 

 arbustoruni, van bifasciata, Kew. From the limestone island 

 of Lismore, in the Firth of Clyde, Rev. G. A. Frank Knight records 

 one specimen- of the var. bifasciata of Helicogona arbustoruni, the 

 specimen having been identified by the late W. Denison Roebuck. 

 The variety differs from the typical form in possessing, instead of 

 one dark brown band encircling the whorls, one or more darker 

 spiral bands. The variety, previously unknown from Scotland, 

 has several English records, and occurs in Switzerland. {Glasgmv 

 Naturalist, vol. viii., 1920, p. 127). 







