OUR LARGEST STANDING ARMY: THE BIRDS. 
328 
bunting, and indigo bird of the food 
in this orchard, and that of the 
species during May under ordinary 
circumstances. The results showed 
that there was a general diminution 
of vegetable and miscellaneous food 
in the orchard specimens to compen- 
sate for the increase of caterpillars. 
The Red-winged Blackbird 
“ Three facts,” says Professor 
Forbes, ‘‘stand out very clearly as 
the result of these investigations : 
‘‘(1) Birds of the most varied 
character and habits, migrant and 
resident, of all sizes, from the tiny 
wren to the blue jay, birds of the 
forest, garden, and meadow, those of 
arboreal and those of terrestrial 
habit, were certainly either attracted 
or detained here by the bountiful 
supply of insect food and were feed- 
ing freely upon the species most 
abundant. That thirty-five per cent, 
of the food of all the birds congre- 
gated here should have consisted of 
a single species of insect is a fact so 
extraordinary that its meaning can- 
not be mistaken. Whatever power 
the birds of this vicinity possessed as 
checks upon destructive irruption of 
insect life, was being largely exerted 
here to restore the broken balance of 
organic nature. And while looking 
for their influence over one insect 
outbreak we stumbled upon, at least, 
two others, less marked, perhaps in- 
cipient, but evident enough to ex- 
press themselves clearly in the 
changed food ratios of the birds. 
“ (2) The comparisons made show 
plainly that the reflex effect of this 
concentration on two or three un- 
usually numerous insects was so 
widely distributed over the ordinary 
elements of their food that no es- 
pecial chance was given for the 
rise of new fluctuations among the 
species commonly eaten. That is 
to say, the abnormal pressure put 
upon the canker worm and vine 
chafer was compensated by a gen- 
eral diminution of the ratios of all 
the other elements, and not by a 
neglect of one or two alone. If the 
latter had been the case, the criti- 
cism might easily have been made 
that the birds in helping to reduce 
one oscillation were setting others 
on foot. 
“ (3) The fact that with the ex- 
ception of the indigo bird, the 
species whose records in the orchard 
were compared with those made 
elsewhere, had eaten in the former 
situation as many caterpillars, other 
than canker worms, as usual, simply 
adding their canker worm ratios to 
those of other caterpillars, goes to 
show that these insects are favorites 
with a majority of birds.” 
One of the most notable series of 
studies upon the relations of birds 
to outbreaks of injurious insects 
was that carried on for thirteen 
years by Professor Samuel Aughey 
of the University of Nebraska, con- 
cerning the extent to which birds 
feed upon the Rocky Mountain 
locust or grasshopper during the 
periodical outbreaks of that insect. 
Fortunately the results of these 
