144 THE BIRDS OF SPRING. 
even the greater part of these latter may be found, if not 
every year, at least occasionally during the early part of 
March. The migratory species constitute two classes, 
according to their range in the breeding season, viz. : 
those species that spend the summer with us, and those 
that altogether pass farther north. Compared with the 
birds of winter, they embrace a very much greater pro- 
portion of common species, while nearly all are regular, if 
not abundant visitors. The proportion of rare species is 
but thirty-five and one-half per cent., instead of seventy- 
six per cent. as in winter. The number of rapacious 
species has hardly increased, but the insectivorous, in- 
stead of being extremely few, now constitute, taking only 
those strictly insectivorous, fully one-half the whole, and 
the diet of this remaining half (especially among the land 
birds) is mainly composed of insects. 
Such are some of the changing phases of bird life in our 
varied climate. In the following tabular statement we 
give a further summary.* 
Whole number of species (in Spring),. . . . 280 
ommon, ‘* een 4 . . 190 
Rare, $e & i i ` x 90 
Migrant, <«“ e hs ee ont D0 
Resident, ‘“ h ‘ e z 30 
Migrants that spend the summer in a Birds, 136 
Southern New England, ‘ "i Water ‘‘ i 
Migrants that pass the summer —— d Birds, 28 
north, i ‘ k k ` Water “ 80 
— 108 
; 18 
ir allies, . 15 
5 TT 
aa 4. 8-8 3 
* ¢* © ee 8 @ 
