s 
TMK RELATION OF BPABBOWS TO AGRICULTURE. 
Fk;. 1.— Cutworm and moth (after Howard 
loaned by Division of Entomology). 
The seed element is of particular interest only when it shows 
destruction of grain or weeds. Injury to grain or fruit by birds is 
usually the most prominent and often the only fact of economic 
ornithology possessed by the layman; yel comparatively few birds 
harm either of these crops, while many species render important 
service to agriculture by destroying weed seed. As has been aptly 
said, a weed is a plant out of place Certain plants seem to have 
formed a habit of constantly getting out of place and installing them- 
selves in cultivated ground, but 
whether actually among crops or 
in adjacent waste land, from which 
they can spread to cultivated soil, 
they are always a menace. In 
the garden they occupy the room 
allotted to useful plants, and ap- 
propriate their light, water, and 
food. Any check on these nox- 
ious interlopers, a million of which 
can spring up on a single acre, 
will not only lessen nature's 
chance of populating the soil 
with worse than useless species, 
but will enable the farmer to at- 
tain greater success with cultivated crops. The hoe and cultivator 
will do much to eradicate them, but some will always succeed in 
ripening a multitude of seeds to sprout the following season. Cer- 
tain garden weeds produce an incredible number of seeds. A single 
plant of one of these species, as purslane, for instance, may mature 
as many as 1.00,000 seeds in a season, and these, if unchecked, would 
produce in a few years a number of weeds utterly beyond compre- 
hension. The habits of some of the common weeds are considered 
in connection with the discussion of 
the value of birds as weed destroyers 
(see pp. 25-28). 
The animal food of the smaller land 
birds consists of insects and spiders. 
The insects belong for the most part 
to the orders Lepidoptera (butterflies 
and moths), Orthoptera (grasshoppers, locusts, and crickets). Diptera 
(flies), Ilemiptera (bugs). Coleoptera (beetles), and llymenoptera 
(ants, bees, and wasps). Lepidoptera, Orthoptera, and Coleoptera 
furnish the bulk of the insect food of birds. The Lepidopterous food 
is taken almost entirely in the Larval condition, and comprises smooth 
caterpillars belonging Largely to the family Noctuida\ which includes 
cutworms (see tig. 1), army worms, and their allies. The Orthoptera 
eaten are principally long- and short-horned grasshoppers (Locustida? 
Fi;;. -'. — Grasshopper (after Riley: 
loaned by Division of Entomology). 
