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.
Trap door traps 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 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/corral traps 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.
Cannon nets 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 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.
Noose traps Birds that walk on the ground can be captured using an array of mono-filament nooses. These are usually placed along favoured feeding, roosting or nest sites. Some raptors are trapped using live-bait and nooses on the cage holding the bait. This trap, also known as a
bal-chatri, has also been adapted to capture other birds such as shrikes. A "noose carpet" is another variant that consists of a number of tiny nooses on a mat.
Birdlime The muscles of perching birds allow the toes to pull inwards with some force but there are no strong muscles to open them up. The application of sticky latex, "
birdlime", often obtained from a local tree to favourite perches is used in many parts of the world to capture small birds. Other variations include the use of a long stick daubed with birdlime that is manually placed over the bird to cause its wings to get stuck.
Spot-light trapping Some birds such as partridges and pheasants can be caught in the night by stunning them with bright light beams. Before the 19th Century, lanterns were used for hunting larks at night in Spain, Italy and England. In Italy the technique was known as lanciatoia and in England it was referred to as
bat-fowling or low belling. ==Other methods used in control and hunting==