As showing how a colony of martins thrives when provided with sufficient room to multiply, an experiment by Mr. J. Warren Jacobs, of Waynesburg, Pa., may be cited.  The first year five pairs were induced to occupy the single box provided, and raised eleven young.  The fourth year three large boxes, divided into ninety-nine rooms, contained fifty-three pairs, and they raised about 175 young.  The colony was thus nearly three hundred strong at the close of the fourth season.  The effect of this number of hungry martins on the insects infesting the neighborhood may be imagined.

From the standpoint of the farmer and the cotton grower, swallows are among the most useful birds.  Especially designed by nature to capture insects in midair, their powers of flight and endurance are unexcelled, and in their own field they have no competitors.  Their peculiar value to the cotton grower consists in the fact that, like the nighthawk, they capture boll weevils when flying over the fields, which no other birds do.  Flycatchers snap up the weevils near trees and shrubbery.  Wrens hunt them out when concealed under bark or rubbish.  Blackbirds catch them on the ground, as do the killdeer, titlark, meadow lark, and others; while orioles hunt for them on the bolls.  But it is the peculiar function of swallows to catch the weevils as they are making long flights, leaving the cotton fields in search of hiding places in which to winter or entering them to continue their work of devastation.

Means have been taken to inform residents of the northern states of the value of the swallow tribe to agriculturists generally, and particularly to cotton planters, in the belief that the number of swallows breeding in the North can be substantially increased.  The cooperation of the northern states is important, since birds bred in the North migrate directly through the southern states in the fall on their way to the distant tropics, and also in the spring on their return.

[Illustration:  THE NIGHTHAWK A Goatsucker, not a Song-bird; but it Feeds Exclusively Upon Insects]

Important as it is to increase the number of northern breeding swallows, it is still more important to increase the number nesting in the South and to induce the birds there to extend their range over as much of the cotton area as possible.  Nesting birds spend much more time in the South than migrants, and during the weeks when the old birds are feeding young they are almost incessantly engaged in the pursuit of insects.

It is not, of course, claimed that birds alone can stay the ravages of the cotton boll weevil in Texas, but they materially aid in checking the advance of the pest into the other cotton states.  Important auxiliaries, in destroying these insects, birds aid in reducing their numbers within safe limits, and once within safe limits in keeping them there.  Hence it is for the interests of the cotton states that special efforts be made to protect and care for the weevil-eating species, and to increase their numbers in every way possible.—­(End of the circular.)