18 The Ottawa Naturalist. [April 



STOMACH CONTENTS OF SOME CANADIAN BIRDS. 



By C. W. G. Eifrig, Addison, III. 



The appended list gives the stomach contents of a small 

 number of birds, the stomachs of which I have examined. In 

 most of the stomachs of small birds, like finches, vireos, and 

 warblers, the investigator who has not unlimited time at his 

 disposal can usually only tell whether the contents is of vegetable 

 or animal origin; in the latter case it takes expert knowledge 

 of the microscopic parts of small insects to unable one to tell 

 what insects have been eaten. The following birds have been 

 selected either for their rarity or because they are well known. 

 The majority have been taken near Ottawa, the others at least 

 in Canada. Several in the list have been bought in the market. 

 The contents of the stomachs of the birds near the end of the 

 list, of which the percentage of the different parts is stated, have 

 been kindly determined for the writer by the Bureau of Biological 

 Survey, Washington, D.C., under the direction of Dr. A. K. 

 Fisher, to whom the writer would extend his sincere thanks. 



Holbcell's Grebe, Colymbus holhcellii; October 17, 1905, a 

 large bunch of its own feathers. 



Horned Grebe, C. auritus; October 10, 1905, a bunch of 

 its own feathers. 



Loon, Gavia imber; May, 20, 1907, bones of fish, including 

 at least one of the Catostomidce (the Suckers). Some of the 

 gravel stones, also found, are at least half an inch long. 



Bittern, Botaurus lenfiginosus; 1. May 12. 1904, several 

 large beetles and other insects; 2. ?, 1905, 1 frog, 2 mice, 8 

 leeches; 3. October 30, 1906, 2 frogs, 2 small sunfish. 



Blue Heron, Ardea herodias; July 25, 1905, 1 fish, six 

 inches long. 



Spruce Grouse, Canachites canadensis; October 31, 1904, 

 pair, male and female, both full of spruce tips. 



Ruffled Grouse, Bonasa umbellus togata; 1. September 

 30, 1904, clover leaves; 2. October 22, 1904, leaves, gravel and 

 sand; 3. October 15, 1904, hawthorn (Cratcegtis) leaves; 4. 

 April 25, 1905, leaves of Goldthread (Captis trifolia), and sharp- 

 edged pebbles of quartz; 5. October 10, 1905, leaves of Aromatic 

 Wintergreen (Gaultheria procumbens) and clover; 6. October 19, 

 1905, clover leaves only. 



Willow Ptarmigan, Lagopus lagopus; 1. January, 1907, 

 (market), stomach filled with ends of willow twigs; 2. January, 

 1909, completely filled with oats. 



Marsh Hawk, Circus hudsonius; September 17, 1907, 2 

 sparrows (Vesper, or Song?). 



