1912.] NATURAL SCIENCES OF PHILADELPHIA. 363 
Fortunately, this is not the case in the United States, where we have 
data enough to prove the point. 
A selection of the more conspicuous cases of refusal of favorite 
natural foods by the birds tested by Judd are given in the following 
tabulation. Other instances are cited in the summaries of the 
separate experiments (pp. 340, 346, 349, 350 and 351). 
Eaten by wild individuals of the 
Rejected by captive birds. 
A ruby-throated hummingbird 
rejected small leaf-hoppers, flies, 
flea-beetles, and spiders. 
A bluejay refused a hen’s egg, 
living birds and mice, and mul- 
same species. 
All of these items are com- 
monly eaten by wild birds of 
this species. 
In a state of nature jays fre- 
quently break up outlying nests 
of fowls. Birds and mice are 
preyed upon and mulberries are 
eaten. Acorns have been found 
in dozens of stomachs of wild 
birds and are a very important 
element of the normal diet. 
English sparrows _ rejected Whole flocks of English spar- 
fruiting heads of dandelion. rows pass days in rifling the ripe 
! involucres of this plant. 
A snowbird, a white-throated 
sparrow, and a song sparrow re- 
fused seeds of lamb’s quarters. 
berries. Acorns also were refused. 
These seeds are a common 
natural food of all three birds. 
All are eaten by wild song 
sparrows, the smartweed seeds 
in abundance. 
The song sparrow rejected, also, 
seeds of smartweed and beetles 
of the genera Diabrotica, Hippo- 
damia, and Lachnosterna. 
These facts show that the feeding reactions of various animals 
are strikingly modified by confinement. Some animals refuse items 
of food which are a favorite with wild individuals of the species, 
some of which may form a notable percentage of the total subsist- 
ence. Others refuse all food. The birds experimented upon by 
Judd together disregarded or rejected 108 articles of food. Forty- 
two of these items have been found in stomachs of wild birds of the 
same species that ignored or refused them in captivity. Investiga- 
tions carried on while this paper was in preparation raised this 
number to 42 from 35, and it must be borne in mind that subsequent 
stomach examinations will increase, never diminish the total. The 
