Bal-chatri (/bɑːl tʃʌθri/) are traps designed to catch

birds of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predat ...

(raptors). The trap essentially consists of a cage baited inside with a conspicuously visible live rodent or small bird, with a series of monofilament nooses attached to the surface to snare the legs of a free-flying raptor that attempts to take the bait. The name is derived from the

Hindi Hindi ( Devanāgarī: or , ), or more precisely Modern Standard Hindi (Devanagari: ), is an Indo-Aryan language spoken chiefly in the Hindi Belt region encompassing parts of northern, central, eastern, and western India. Hindi has been ...

word used by trappers in India. Modified bal-chatri traps are also used for catching shrikes.

History

The bal-chatri originated in

East India East India is a region of India consisting of the Indian states of Bihar, Jharkhand, Odisha and West Bengal and also the union territory of the Andaman and Nicobar Islands. The region roughly corresponds to the historical region of Magadh ...

as a trap developed and used by falconers to catch suitable birds of prey to train for use in

hunting Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products ( fur/ hide, bone/tusks, horn/antler, ...

. It consisted of a small, conical, cane

cage A cage is an enclosure often made of mesh, bars, or wires, used to confine, contain or protect something or someone. A cage can serve many purposes, including keeping an animal or person in captivity, capturing an animal or person, and displayin ...

, containing live lure birds to attract raptors, and covered with attached

horsehair Horsehair is the long hair growing on the manes and tails of horses. It is used for various purposes, including upholstery, brushes, the bows of musical instruments, a hard-wearing fabric called haircloth, and for horsehair plaster, a wallc ...

noose A noose is a loop at the end of a rope in which the knot tightens under load and can be loosened without untying the knot. The knot can be used to secure a rope to a post, pole, or animal but only where the end is in a position that the loop can ...

s to entangle their feet. The term bal-chatri ( hi, बाल छत्री) has been mistranslated as “boy’s umbrella”, or “small umbrella”, after their shape but is correctly translated to "hair umbrella" and refers to the nooses made of horse-hair anchored to the umbrella-like frame. Bal-chatris continue to be used by falconers, but are also used in ornithological research projects which require the capture of raptors for banding and other procedures, such as blood sampling.

Methodology and use

Contemporary traps are made of more modern materials, such as

wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is c ...

mesh A mesh is a barrier made of connected strands of metal, fiber, or other flexible or ductile materials. A mesh is similar to a web or a net in that it has many attached or woven strands. Types * A plastic mesh may be extruded, oriented, exp ...

cages with nooses made of

nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from pe ...

monofilament. The traps vary from 25–50 cm in diameter or length, with the nooses 4–12 cm in diameter. They are normally weighted to prevent them from being carried away by ensnared birds. The live lure, or bait, animals used for the trap are usually rodents such as

house mice The house mouse (''Mus musculus'') is a small mammal of the order Rodentia, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus''. Although ...

. The cage may have a double wall, or a removable roof or inner compartment, both to protect the bait animals from the raptors, and to prevent them damaging the nooses by chewing them. The traps are designed to be highly portable and may be deployed opportunistically from a slowly moving vehicle on a roadside when a hawk or falcon is sighted perch-hunting from a pole or utility line along a road. They may also be used near nesting sites in order to trap a breeding pair. Active traps require continuous monitoring. Users require proper training; there are ethical considerations and the need for experience in the use of bal-chatris to avoid harming, and minimizing temporary stress to, the bait animals and the raptors caught.

History

Methodology and use

References

Further reading