4o4 Recent Literature. LJuly 



in every way, and in making a special plea for investigations in economic 

 ornithology upon which, alone, rational treatment of birds can be based. 



Two of Dr. Collinge's articles relate to fish-eating birds, in one of which 2 

 it is pointed out that past statements on the matter have not been based 

 on careful investigation, and preliminary results are announced of a study 

 begun under the auspices of the Carnegie Trust for the Universities of 

 Scotland. More than 3000 specimens representing 14 species have been 

 examined, and the striking results are that "fish does not constitute the 

 bulk of their food or anything like the major portion of it," that only 

 two species, the Cormorant and the Shag, are purely fish-eaters, that only 

 one other, the Common Tern preys chiefly on fish, and that 1 1 of 14s pecies 

 consume fish to the extent of less than 20 percent of their food. The diet 

 of the Black-headed Gull is treated in some detail, with a conclusion 

 favorable to the bird. 



The Kingfisher is the subject of the second paper 3 on fish-eating birds; 

 the bird's habits are sketched and a report is presented on the examination 

 of stomach contents and food remains taken from nesting burrows. Aver- 

 aging results from both sources, Dr. Collinge shows that 61.5 per cent of 

 the Kingfisher's food consists of fish, 12.52 of which is trout. Stated in 

 economic terms, 13 per cent of the birds food is taken at man's expense, 

 16 per cent contributes to human welfare and 71 per cent is neutral. An 

 especially interesting feature of the analyses is the close agreement between 

 the proportions of the principal items of food in the material taken from 

 stomachs and in the disgorged indigestibles from the nest. A table of 

 percentages exhibiting this relationship follows: 



From stomachs From nests 



Fish 63.5 59.5 



Mollusks 4.0 4.0 



Tadpoles 3.5 5.5 



Injurious Insects 16.5 15.5 



Neutral Insects 6.0 4.5 



Crustaceans 3.5 6.5 



Worms 1.5 1.5 



Thus it is quite evident that digestion, (at least so far as it is carried 

 by pellet-disgorging species) does not materially alter the relative volumes 

 of food items. The reviewer believes that this condition extents to excre- 

 ment also, at least in the case of nestlings, and elsewhere 4 he has urged 

 study of this evidence as to food-habits. The particular importance of 

 Dr. Collinge's findings lies in the validity they give to analyses of materials 

 which can be collected and studied without destruction of bird life. 



2 Sea-birds: Their Relation to the Fisheries and Agriculture. Nature, April 8- 

 1920, reprint, 7 pp. 



3 The Kingfisher — Is It Injurious? Illustrated Sporting and Dramatic News, 

 March 6, 1920, reprint, 1 galley. 



" Bui. 32, U. S. Biological Survey, 1908, pp. 23-24. 



