168 THE UNIVERSITY OF THE STATE OF NEW YORK 



Larvae of Cabbage Butterfly on Cabbage 



Leaf. (1916) Nrq C4 



Canker worms, mourning warbler Nu WN 



Cut worms, bluebird Nu Bm 



All garden insects, wren Nu WrH8 



2 Birds as destroyers of weed seeds 



Some birds, like the mourning dove and goldfinch, feed upon 

 weed seeds at all times of the year; others, like the majority of 

 sparrows, feed upon insects during the summer and seeds during 

 the rest of the year. Some of the greatest weed destroyers are 

 winter residents with us and feed upon such weeds as project 

 above the snow. 



Prairie horned larks Nu LdP9 



Tree sparrow Nu SpT8 



Song sparrow and white-throat Nu SpR72 



Fox sparrows Nu SpG 



Junco Nu JuS 



Goldfinch Nu Go 



3 Birds as destroyers of rodents 



Still more important are certain birds in the destruction of 

 small rodents. A conservative estimate puts the possible off- 

 spring from one pair of meadow mice at 35 a year. At this rate 

 it would take but five years to produce over three million mice 

 from one pair. A single mouse can be quite destructive and 

 when there are many the aggregate destruction often amounts 

 to thousands of dollars. During the winter mice often work 

 under the snow and girdle even rather large trees. Every hawk 

 and owl requires the equivalent of three mice a day to live, or 

 over a thousand a year. 



a General 



Owl pellets Nu Ow9 



Owls have the habit of swallowing their prey whole, bones, 

 fur and all and later ejecting from the mouth the indigestible 

 parts in the form of pellets. By examining these pellets, one can 

 determine what they have been feeding upon. 



Nest of great horned owl Nu OwG3 



Food of great horned owl Nu OwG9 



b Beneficial hawks 



Red-tailed . Nu HR9 



Sparrow hawk Nu HT 



