One sometimes wonders that birds manage to exist and to actually increase in numbers. Possibly the first group of enemies should include men and boys who kill adult birds, leaving the fledglings to starve, or who rob the nests of eggs. It is the writer's belief that every boy who makes one or more of the projects in this booklet, and sees it occupied, will become one of a growing number who will care for instead of destroy the birds of his neighborhood. Further, if every man who now thoughtlessly or willfully destroys birds, knew the real money value of the work birds do, he would build or buy houses and food shelters to increase Nature's best friends to mankind.

The second group of enemies include ants and other vermin which at times infest nests and nesting boxes, snakes, squirrels, mice and rats. Protection against this group is afforded by bands of tin about the pole, or spikes of wood or metal pointing downward so that access is impossible by climbing up the pole. Another protection is to make the entrance holes small enough to admit only the occupant for whom the house was intended. Of course, the houses for the larger birds must be protected in other ways. Charles Tesch of Milwaukee suggests a sticky fly paper compound made of resin (melted) and castor oil as a preventive for the inroads of the small red ant, if suitable support is available.

The final group consists of the two worst foes of bird life, cats and English or house sparrows. If you really value the birds that have been reared in the house you have built you may need to get up early more than one morning when the youngsters leave the nest to protect them from the highly respectable (?) tabby that lives possibly next door if not at your own house. It often comes to a choice between cats and birds: and the cats may be disposed of in two ways—the right kind of box traps for the homeless and unknown robbers, and an air rifle with sufficient "sting" for the trespasser from next door. A few lessons of this kind usually have some effect.

The English or house sparrow was introduced into this country about a half-century ago. It has spread over practically all of the United States and Southern Canada. Possibly no bird has exhibited such powers of adapting itself to new conditions. The sparrow is no respecter of places for locating its nest. It lives on a variety of foods changing from one to another as the necessity arises. In spite of opposition, this bird is constantly on the increase, so much so that in many cases more desirable native birds have been obliged to leave. The sparrow is filthy and quarrelsome, and lives mainly upon valuable small grains in every case where this is possible. There are two methods possible which afford partial relief: (1) traps and (2) driving them away with an air-rifle. Traps are usually successful for a comparatively brief time, since the sparrows soon associate the trap with danger and so avoid it. A very successful type of woven wire trap is advocated by the Department of Agriculture but is probably beyond the ability of the average boy to make well. It sells by commercial manufacturers of bird supplies for about $4.00. This trap works all the year around as it depends upon the attraction of food. Fig. 65 gives a simple, yet effective trap. However, it requires the presence of some hidden observer to spring it at the right moment. Another type of trap is based upon the nest-house idea. Its effectiveness is limited largely to the nesting season, though it may be used by the birds for shelter. One of the most efficient traps was invented by Charles Tesch, of Milwaukee, Wis. Its principle is that of a tipping chamber leading into a sack thru a chute. Fig. 64 gives the dimensions to be followed in making such a trap. The inventor says that the bag should be far enough away from the box to make certain that the victim has no chance to tell the others what happened to him by chirping, otherwise they will no longer enter the trap. The box must be perfectly tight in order to prevent drafts from issuing thru the entrance which will cause sparrows to keep away. If a few feathers are glued or shellacked to the tipping chamber floor, the sparrow is often attracted more strongly. The bag should be examined frequently to liberate bluebirds and wrens, who may have been caught.

FIG. 64. (SPARROW TRAP) FIG. 64.

FIG. 65. (SPARROW TRAP) FIG. 65.

However, fighting bird enemies without the cooperation of neighbors is not an easy matter. In the case of sparrows, so many more are left that traps alone are ineffective. An airgun properly used offers some help in the city to drive them away from the premises, while a shot gun or 22 caliber rifle are more effective in the country. If every sparrow nest were torn down and no place given them in your neighborhood, the pest is likely to avoid your grounds. Finally, keep nesting boxes free from sparrows while the owners are away for the winter.