460 ECONOMIC RELATIONS OF OUR BIRDS. 
FRUIT-EATERS. 
For the vicinity of Ithaca, 
Number of species observed. 3 
Number of individuals observed. 
Average number per mile. . 'I'd 
For Jefferson county. 
Number of species observed.. 3 
Number of individuals observed. 37 
AA'erage number per mile. 3— 
. SEED-EATERS. 
For the vicinity of Ithaca. 
Number of species observed. 10 
Number of individuals observed. 576 
Average number per mile. 23 -e 
For Jefferson county, 
Number of species observed. 12 
Number of individuals observed. 141 
Average number per mile. 9 + 
FLY-CATCHERS. 
For the vicinity of Ithaca. 
Number of species observed. 10 
Number of individuals observed. 255 
Average number per mile. 10 + 
For Jefferson county. 
Number of species observed. 8 
Number of individuals observed. 106 
Average number per mile. 7 + 
INSECT-EATERS. 
For the vicinity of Ithaca. 
Number of species observed.I. 8 
Number of individuals observed. 69 
Average number per mile. . 3— 
For Jefferson county. 
Number of species observed. 14 
Number of individuals observed. 116 
Average number per mile. 8— 
These figures appear to indicate that the greatest difference between the two 
localities exists among the Fruit-eaters, the Seed-eaters, and the Insect-eaters, 
the first two classes being much more abundant at Ithaca, while tlie Insect- 
eaters are much more abundant in Jefferson county. Much less weight can be 
given to these figures than to those considered under the last head. They sim¬ 
ply indicate a dii'ection in which observation needs to be made. 
(4) Some birds may be injurious to a locality ivhich they seldom or never visit. 
O'he migratory movements which characterize most birds subject them to a 
great vai-iety of enemies. The boreal birds of prey, which live in the summer 
homes of all our birds of passage, and of all our winter visitants, are as in¬ 
jurious to us, so far as they destroy the members of these classes, as though 
they did the work of destruction in our midst. The same is to be said of those 
