ECONOMIC IMPORTANCE OF BIRDS 
115 
wren, blackbird, etc., which feed principally on insects 
that are found on or near the ground. The insects that 
fly, like mosquitoes, gnats, and house-flies, are eaten by 
swifts, swallows, night-hawks, kingbirds, and fly-catchers. 
Among the hawks and owls is found a long list of bene¬ 
ficial birds, for the screech owl, red-tailed hawk, and the red¬ 
shouldered hawk are almost without exception valuable as 
Figure 103 . — Eggs of the Woodcock. 
The nest is merely a depression in the leaves with no lining. The young 
leave the nest within a few hours after hatching, so that a nest to hold the 
young would be useless. Young that leave the nest soon after hatching are 
called praecocial. 
destroyers of shrews, moles, mice, rats, weasels, and rabbits. 
The hawks that are partly harmful are the sharp-shinned 
hawk, Cooper’s-hawk, and the marsh-hawk. All these help 
themselves to poultry and feed on small beneficial birds 
like the song-sparrow and bluebird. 
The exact relation of birds to agriculture and the foods that 
they eat has been a subject of study by the Department of 
