THE BLUE JAY AND ITS FOOD. 199 
EXAMINATION OF STOMACH CONTENTS. 
One of the first points to attract attention in examining these stom- 
achs was the large quantity of mineral matter, averaging over 14 per 
cent of the total contents. The real food is composed of 24.3 per vent 
of animal matter and 75.7 per cent of vegetable matter, ora trifle more 
than three times as much vegetable as animal (fig. 41). The animal 
food is chiefly made up of insects, with a few spiders, myriapods, 
snails, and small vertebrates, such as fish, salamanders, tree frogs, 
mice, and birds. Everything was carefully examined which might 
by any possibility indicate that birds or eggs had been eaten, but 
remains of birds were found in only 2, and the shells of small birds’ 
eggs in 3of the 292 stomachs. One of these, taken on February 10, con- 
tained the bones, claws, and a little skin of a bird’s foot. Another, 
7 
Jan.| Feb. | Mar.| Apr. | May | June |July | Aug.} Sep.| Oct. | Nov. | Dec. 
—— 
Ui; 
\— 
i 
—_/f (As 
SY, Gy 
FG LD 
x A; : 
E= = Vegetable food. ; 343 Useful insects. 
WZ Noxious insects. HEE) “Miscellancous animal food. 
Fia. 41.—Diagram showing the relative amounts of vegetable and animal food eaten by the blue 
jay in each month of the year. The vegetable food is represented by the area above the line 
AB; the animal food by the space below. 
taken on June 24, contained remains of a young bird. The three 
stomachs with birds’ eggs were collected in June, August, and October, 
respectively. The shell eaten in October belonged to the egg of some 
larger bird like the ruffed grouse, and considering the time of year, 
was undoubtedly merely an empty shell from an old nest. Shells of 
eggs which were identified as those of domesticated fowls, or some 
bird of equal size, were found in 11 stomachs, collected at irregular 
times during the year. This evidence would seem to show that more 
eggs of domesticated fowls than of wild birds are destroyed, but it is 
much more probable that these shells were obtained from refuse heaps 
about farmhouses. 
