PSBO’s Skagit Raptor project utilizes three raptor trapping techniques to capture raptors for banding. All three were developed by falconers in India many centuries ago. These techniques take advantage of raptors’ hunting behaviors to capture them.
The bal-chatri is a versatile trap that can be used to capture many species of raptors. It is particularly effective for such species as red-tailed hawks, Cooper’s hawks, and American kestrels, and is the primary trap used to capture these three species for the Skagit project. A bal-chatri is essentially a small cage, often in a half cylinder, conical, or rectangular shape, with many monofilament nooses attached to the exposed surfaces. A lure animal, such as a mouse or non-native bird is placed in the cage. The trap is then deployed within sight of a perched raptor, often from a car along roadsides. The movement of the lure animal will attract the raptor, and when the raptor flies down and lands on the trap, the nooses will ensnare the raptors toes and feet.
The dho-gaza trap can also be used for many species, but is particularly well suited for capturing falcons. The Skagit project uses dho-gazas to capture merlins. A dho-gaza is essentially a small net attached at its four corners to some sort of pole frame. The net is attached in such a way as to be easily pulled off its pole frame – for example, with paperclips. A cinch-line string attached at one end to the pole frame is run through the outer mesh squares of the net along all four sides, and then attached again to the frame. A lure animal, such as a tethered house sparrow or starling, is used to attract the raptor. The trap is positioned within sight of a raptor, and perpendicular to the path the raptor is expected to take to get to the lure animal. The lure animal is placed on the opposite side of the net as the raptor. The movement of the lure animal will attract the raptor and it will make a stoop down to capture the lure. But before it gets to the lure the raptor will hit the net, which will detach from the pole frame, and the cinch-line string will close the net behind the raptor, effectively forming a net bag around the raptor.
The phai, or hoop trap, is a good trap for falcons and accipiters. The Skagit project uses a phai trap to capture merlins. The trap is a hoop, such as a hoop made out of a wood dowel, and has many upright nooses placed all along its length. A lure animal, such as a non-native bird, is placed in the center of the hoop. The trap is deployed within sight of a raptor. The lure animal appears to be an easy meal for a raptor to scoop-up in-flight. The raptor dives down toward the lure animal and as it extends its legs to grap the lure, its legs are ensnared by the hoop’s nooses. Compared to the dho-gaza, this trap has the advantage of being able to capture the raptor from any angle of approach, as the hoop and nooses encircle the lure.
To learn more about the Skagit Wintering Raptor Project, visit the project’s web page.