1913 



FOR DUCKS IN NORTHERN ONTARIO. 



11 



an idea of the relative importance of the various constituents of the food of the 

 ducks in this region at this season of the year. A summary of the results for the 

 different groups of ducks is given below. The percentage of animal food is bulked, 

 except in the case of the Mergansers. 



ESTIMATED PERCENTAGE OF THE VARIOUS CONSTITUENTS OF DUCK FOOD 



5 Mergansers 

 Oct 22-30, 1912 



Dragon-fly nymphs 62% \ 



Caddis-fly larvae 24 " n nn f/ 



Crawfish 12" f 



Fish 2 " J 



Vallisneria seed 1 % 



Of the gizzards of the Blue-bills, only one contained any animal food. This 

 consisted of several dragon fly nymphs and a caddis fly larva. The most important 

 plant seeds were those of the water mill foil (Myriophyllum) and of the wild 

 celery (Vallisneria). Potamogeton seeds were also found in considerable amounts. 

 In several there were the recognizable remains of leaves of various water plants, 

 Potamogetons and wild celery. This part of the Blue-bills' food is probably much 

 more important than appears to be the case on first sight, because the leaves of the 

 plants are crisp and delicate and would soon be destroyed in the gizzard. 



Of the eight Buffle-heads, only one had any animal food two dragon fly 

 nymphs and a water beetle and small fish. Of the plant food the seed of Vallis- 

 neria was found in all and formed the most important content of the gizzard. 

 There was also a considerable amount of different Potamogeton seeds. In one 

 instance the Potamogeton seed was the most important food. 



The contents of one Whistler's gizzard consisted entirely of plant material and 

 in one only animal food was found. The seed of the wild celery was by far the 

 most abundant plant food, though small amounts of Potamogeton and Myriophyl- 

 lum seed were found. Of animal food material the dragon fly nymphs were most 

 important. Caddis fly larvae and water bugs and beetles were also found. 



In only one of the five Mergansers was there a trace of vegetable food a few 

 seeds of Vallisneria and some traces of leaves, probably of the same plant. 

 Animal food was present in abundance. In all there were found dragon 

 fly nymphs (larvae) and caddis fly larvae, the dragon fly larvae, however, being much 

 the more important. In one gizzard a cray fish was found over 3 inches in length. 

 In the same gizzard there were also the scales and other remains of an ordinary 

 fish a minnow (?) 2-3 inches long. 



Mr. W. A. Clemens, B.A., of the Department of Biology, kindly ^identified the 

 animal remains in the gizzards and gave me the information on the habits of the 



