Bird trapping

Bird trapping techniques to capture wild birds include a wide range of techniques that have their origins in the hunting of birds for food. While hunting for food does not require birds to be caught alive, some trapping techniques capture birds without harming them and are of use in ornithology research. Wild birds may also be trapped for their display in captivity in zoological gardens or for keeping as a pet. Bird trapping was formerly unregulated, but to protect bird populations most countries have specific laws and regulations.

Birds are lured into the vicinity of traps through the use of suitable habitat patches where the birds are known to visit. A specific location may be further modified by the provision of food, the use of decoy birds, the use of calls, or owls that may induce mobbing. Male birds of some species are used as decoys during the breeding seasons to challenge and beckon other males from nearby. Larks were formerly attracted using a rotary paddle, sometimes with shiny mirrors attached, turned by a spring. The phrase "a mirror for larks" was once a common metaphor for a trap. Owls and their calls are often used to bring birds out of dense vegetations. The technique has also been used by birdwatchers.

Almost all traps involve the use of food, water or decoys to attract birds within range and a mechanism for restricting the movement, injuring or killing birds that come into range. Food, water, decoy birds and call playback may be used to bring birds to the trap. The use of chemical sprays on crops or food can have more widespread effects and are not usually included in trapping techniques although there are some capture techniques that make use of bait with stupefying agents. The mechanism can be physical and non-lethal like a noose that tightens around the leg or lethal like in deadfall traps. Lethal techniques have been used for the control of birds considered as pests or can be used in the capture of birds for food. Traps can vary in their design to capture individual birds or large flocks and are adapted according to the habitat and behaviour of the birds. Trapping is regulated in most countries and needs to be operated by trained research personnel and failure to follow precautions can lead to injury or death of birds.

Introduced in 2011, trap door traps are humane box traps with a spring-loaded lid and feeding platform. The trap attracts target birds to feed and is triggered when the bird steps on a perch. The trap then drops the bird via gravity into a quiet, comfortable space until they are ready for live removal and relocation. There is no stress to the bird – no part of the trap makes contact nor does a human touch. These traps offer flexibility in bait and attraction techniques, can be outfitted with an internal catch bag for bird removal, and some include a means to send a notification to a phone or remote operator that a bird has been captured. Trap door traps are most often used for relocating small birds that have entered public buildings and structures such as warehouses, atrium and airport terminals.

Clap traps are spring-loaded frames with netting that are set up in two parts that come together rapidly when triggered by birds or manually controlled to enclose birds. They are usually used for ground birds but some variants are used in shallow water for the capture of waterfowl. Clap traps may be placed at a location habitually used by birds or can include luring devices.

Funnel traps have a narrow entrance into which birds may be lured or driven and the entrance typically leads to larger holding pen or corral (which also gives them the name of corral trap). Funnel traps can be very large and a particularly well-known large scale form was devised in the German bird observatory at Heligoland and are termed as a Heligoland trap.

Flocking birds are sometimes trapped using a large net which is thrown using a series of synchronized cannons or rockets that shoot a weight that drags a net behind it over the entire flock. These nets are also called rocket nets or boom nets. Capturing entire flocks can be an important tool for studies where large numbers of birds need to be examined (such as when monitoring for viruses) or when the birds are gregarious and social. These techniques are used especially in open habitats and are particularly suited for waders and waterbirds. After examination, ringing or other operations, the captured birds are usually released together rather than individually.

Mist nets are fine nets that are suitable for capturing birds in woodlands. The fine net is strung across trees so as to lie in the flight path of a bird. A bird flies into the nearly invisible net and falls to a fold at the bottom of the net where it usually gets entangled. These nets are used especially in bird ringing and are typically never left unsupervised. A bird that falls is quickly removed to avoid injury to the bird and to prevent it from falling prey to predators.