INDEX TO PAPEES RELATING TO FOOD OF BIRDS. 11 



synopsis of the remaining vegetable food and of the insect and other animal 

 food. Tabulations of the principal food items, by months, follow the general 

 account of each species, and diagrams graphically conveying the same infor- 

 mation are given for the bobolink, cowbird, and red-winged blackbird. 



Bulletin 15. The relation of sparrows to agriculture. By Sylvester 

 D. Judd, Ph. D. 98 pp. 4 pis. 19 figs. 1901. 

 The introductory matter in Bulletin 15 comprises a statement of the impor- 

 tance of sparrows, a general account of the principal constituents of their food, 

 and a description of the methods of ascertaining the economic value of birds, 

 including observations in the field and examination of stomachs in the labora- 

 tory. Under the food of sparrows as a group are discussed mineral substances 

 found in sparrows' stomachs, food neutral in effect on agriculture, food inju- 

 rious in effect, and food beneficial in effect. The behavior of sparrows and 

 their habits of feeding in the natural state are described at length, and results 

 of experiments with captive birds are compared with those of the investigation 

 of stomach contents. The caged sparrows were also used to test the efficacy of 

 the various so-called " protective " adaptations of insects, and the resistance 

 of certain hard-coated seeds to the digestive action of the birds. The remainder 

 of the bulletin is devoted to a discussion of the food of sparrows by species. 

 Details of the animal and vegetable food of 26 species are given. Plate IV 

 shows the percentages of the principal food items of 6 species by the graphic 

 method of proportionate sectors of circles. The bulletin contains casual refer- 

 ences to the food of numerous species of birds not formally treated. 



Bulletin 17. Birds of a Maryland farm. A local study of economic 

 ornithology. By Sylvester D. Judd, Ph. D. 116 pp. 17 pis. 

 (lmap). 41 figs. 1902. 

 " Birds of a Maryland Farm " is an account of the relations of all the birds 

 occurring on a 230-acre farm near Marshall Hall to all of the animals and plants 

 used by them for food. Several pages are devoted to a discussion of the local 

 distribution of birds as influenced by topography, nesting facilities, and food 

 supply. In Chapter II is described the behavior of birds during periods of 

 unusual abundance of certain insects, as well as their relations to useful 

 insects and to the standing pests of the various cultivated crops, trees, shrubs, 

 and herbage. The food of the nestlings of several species is described in detail. 

 Chapter III deals with the birds that prey upon poultry, wild birds, fish, carrion, 

 mice, and rabbits, and Chapter IV with those that eat wild and cultivated 

 fruit; this chapter contains also notes on the distribution of seeds by birds. 

 The principal grain eaters are treated in Chapter V and the consumers of weed 

 seed in Chapter VI. The remainder of the bulletin is devoted to a discussion of 

 the food by species or by larger groups. Bulletin 17 represents the results of 

 the most complete study of local economic ornithology that has been made. It 

 gives notes on the food of no fewer than 133 species of birds. 



Bulletin 21. The bobwhite and other quails of the United States in 



their economic relations. By Sylvester D. Judd. 66 pp. 2 pis. 



(1 colored). 10 figs. 1905. 



Two-thirds of this publication is devoted to a single species, the bobwhite. 



The discussion of the general habits of the bird, its value as food, as an object 



of sport, and as an asset on the farm, is very full. The decrease in numbers 



of the bird, legislation in its behalf, and measures for preservation and propa- 



