Traps Are Varied And Ingenious

The first trap widely used by banders (and still popular) was a funnel type, known as the government sparrow trap, because it was designed in 1912 by the Department of Agriculture for farmers trying to get rid of house (or "English") sparrows. It is good not only for these pests (which nearly all banders despise) but for many of the 30-odd species of native American sparrows (which are beneficial and a delight to the eye and ear) and a wide variety of other small birds. Lured by such baits as seed and bread crumbs, the birds push through the first funnel, which ends in a horseshoe of converging wires. What looks like "the way out" proves to be another funnel, leading to a second compartment, so the birds are double-trapped. When the bander is ready to collect them he shoos them into a gathering cage which may be permanently attached or hooked on over a small door opening when needed.

One of the simplest traps is bottomless and box-shaped, made of hardware cloth, welded wire or fine-gauge (1/2-inch to 3/4-inch) chicken wire. It is propped up over the bait or the nest of a ground-breeding species. One long edge is supported by a stick (which may be hinged for quicker action) with a string attached. When a bird is beneath the trap the bander pulls the string.

Still relatively simple, but automatic so that it need not be watched continuously, is a cage-shaped trap with a hinged "doorstep" set at a slight upgrade. When the bird jumps on the step it trips an attached trigger wire, and a sliding door slams down behind it. Named for the late Miss Jessica A. Potter of Los Angeles who designed it in the 1920s, the Potter trap has been made with many modifications, notably multiple cells—one trapped bird tends to attract others whose curiosity lands them in the clink—and glass backs.

Water is a good bait, so in the chardonneret trap (French for goldfinch) there are tiny pans mounted on cocked trigger bars which spring an overhead door when a bird drops in for a quick one.

Deservedly popular is the well-named all-purpose trap, shaped like a double-letter S and modified by Seth H. Low of the FWS from an earlier clover-leaf design. The sides are hardware cloth, 2 feet high and 10 feet long; the top can be hardware cloth or chicken wire. In a permanent layout the trap can be set on concrete to discourage rodents from digging their way in and out. In any setting it works best when there is a shallow pool at one end: the important thing is to have a slow, steady drip of water into the pool to attract attention. A galvanized pail with a small hole, half plugged with a loose-fitting nail, will get as many birds as a more elaborate hydraulic system. The birds get in through a narrow, funnel-shaped entrance.

Even so wily a bird as the crow still has markedly limited intelligence. Modifications of an Australian crow trap are springing up in U.S. gardens: usually 6 feet high and 10 feet square, they have panel-shaped entrances at the top. The crows hop down to feed on corn on the cob. Surprisingly few of them are smart enough to try to fly upward and out the same way. If they do they are discouraged by the jangling of wire coat hangers strung just under the entrance—which did not deter them from getting in.

Exotically named in keeping with its origin and purpose is the Bal-Chatri trap, developed in the Orient for catching falcons and adaptable to most birds of prey. A cone-shaped cage, it holds live bait—one good use for house sparrows, though a house mouse is best. Attached to the top are dozens of nooses, originally of strong silk, now usually of fine nylon leader. Banders driving along a country road spot a sparrow hawk (American kestrel) perched on the wires ahead. Almost beneath the bird they slow down; the passenger opens the car door and drops the trap on the road shoulder. By the time they stop, 100 yards beyond, to look back, the hawk often has his feet caught in a cat's cradle of nooses.

In Europe whole gardens have been converted into traps as elaborate and durable as Hampton Court Maze, but in North America the more costly and permanent layouts are generally reserved for waterfowl. An adaptation from the Dutch, who gave us the word decoy, is the decoy pipe-actually a tunnel, up to 150 feet long, over a curved "pipe," or waterway, dug out as an extension of a shallow pond. The sides have footings of stone or lumber; above that, to a total height of 7� feet, is wire. At the inner end, around the curve and invisible from the pond, is a catching pen 4 by 8 feet, with a gathering cage attached. Baited with shelled corn outside and cob corn inside, the pipe may take hundreds of ducks at once.

The ambitious Colorado trap, usually 25 by 50 feet, consists of netting set over and around steel posts standing in shallow water at a pond's edge. The entrances are on the land, where the trap extends about four feet over a feeding lane. Birds are first baited in with barley spread along a quarter of a mile of shore line. The feed is gradually concentrated to get the birds into the trap. After feeding, they plop into the adjacent water to drink and rest—and wait to be driven into gathering pens.

In all, probably as many ducks are caught for banding in simple, portable traps, with wire sides and top which swivel readily (on doweling, bamboo or Duralumin rods) for folding and portability. One of the handiest, only 2 by 3 by 1� feet, designed by the FWS's law-abiding John J. Lynch, is unabashedly called the Maryland violator trap in honor of the lawbreakers from whom it was copied.