Because all species of hawks are protected in the United States, it is important to catch a hawk alive and unharmed. One of the easiest traps to build and use is a bal-chatri trap. The trap consists of a small cage that contains some type of prey animal, such as a mouse or pigeon. It has many little nooses made of monofilament line on the outside of the cage. When the hawk pounces on the prey, its talons get entangled in the nooses. The hawk will be unable to fly due to the weight of the trap. It can then be safely captured.
Cut a section of the hardware cloth 12 inches by 24 inches wide. Cut the ends of the wires so they form wire points along the edges of the hardware cloth and can be bent easily later.
Fold 6 inches on each end of the 24-inch length up to form two walls. Bend the center section along the 24-inch length into a half-circle until the ends of the hardware cloth walls meet. Bend the wires on the edges of the hardware cloth together to connect the ends. This forms the body of the cage.
Cut two half circles of hardware cloth that will cover the ends of the cage. Place each half-circle in place on the cage and bend the wire points on the edges of the cage to hold the half-circles in place. Ensure that all of the points are bent flush and do not protrude.
Cut a square large enough for a bait animal to fit through out of one of the half-circles. Trim the edges of the square so no wire points remain. Cut a section of hardware cloth large enough to cover the square. Trim the top, bottom and right edges of the section, so that no wire points remain. Leave the wire points on the left edge and wire it in place on the half-circle to form a door.
Wire the metal pipe firmly to the bottom of the cage. This will act as a weight to prevent the hawk from flying off once trapped.
Cut an 8-inch length of monofilament line. Tie a small, strong loop knot in one end of the line. Thread the other end of the line through the loop to form the noose. Tie the other end of the line to one of the wires in the top of the cage. Trim any excess line. Repeat this process until the top of the cage is covered with nooses.