Bird capturing has been practiced for centuries for a variety of purposes, from collecting scientific data to keeping birds as pets. There are several methods that can be used to capture birds, but some techniques are more commonly used than others due to their effectiveness, cost, practicality and ethical considerations.
Catching Birds by Hand
Catching birds by hand is one of the oldest and simplest methods of capturing birds. It involves carefully approaching the bird and quickly grabbing or netting it by hand. This technique requires stealth, speed and some skill to avoid injury to the bird or handler. Hand-catching is most effective for larger bird species on the ground or low vegetation. It allows for selective capture of specific individuals but is quite labor-intensive.
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Hand capture can be highly selective but requires a lot of time and effort per bird captured, so it is generally not practical for large-scale bird capturing operations.
Mist Nets
Mist nets are fine, nearly invisible nets that are used to passively capture birds in flight. Nets are usually set up between poles or vegetation across flight paths used by birds. When birds fly into the net, they become entangled and can then be extracted and handled by researchers. Mist nets are a popular method among ornithologists for capturing wild birds for banding and research.
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Mist nets can capture many birds with relatively little effort but require constant monitoring and expertise to use safely. They are non-selective and so are best suited to general bird population surveys rather than targeting particular species.
Funnel Traps
Funnel traps are enclosures with a small opening or series of openings that birds can enter but have difficulty exiting. Funnels or one-way openings allow birds to pass into the trap but not back out. Traps are baited with food or decoys to attract target species. Once inside, birds can be captured by hand or removed using small clap traps or remote-controlled drop doors.
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Funnel traps can efficiently capture large numbers of birds with minimal effort but require regular monitoring and baiting. They are more selective than mist nets but may still capture non-target species attracted to the bait or structure.
Cannon Nets
Cannon nets utilize explosive charges to rapidly propel a large net over birds to capture entire flocks at once. Nets are laid out on the ground over bait and triggered remotely when birds are positioned underneath. The nets are propelled up and over the birds by small explosive charges. Cannon nets allow researchers to capture dozens or even hundreds of birds in a single deployment.
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Cannon nets are highly effective at capturing entire flocks in one go but are non-selective and carry some risk of injury due to the explosive propulsion method. Their use requires specific permits and training for safe operation.
Chemical Capture
Chemicals such as alpha-chloralose or inhalant anesthetics can be used to temporarily immobilize or sedate birds for easy capture. Chemicals are distributed on bait which birds ingest or incorporated into mist nets. Once sedated, birds can be collected and handled for banding or research purposes. Effects wear off after a period of time with no lasting harm to the birds.
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Chemical capture makes collecting birds easier but carries risks if dosages are not properly calibrated. The ethics of drugging wildlife also make this an unpopular technique among some researchers and the public.
Conclusion
In summary, mist nets and funnel traps are likely the most commonly utilized methods by ornithologists and biologists for bird capturing today. Mist nets are the best technique for general bird population surveys and allow passive mass capturing of most bird species. Funnel traps are more selective and require less constant monitoring than mist nets once set up. Other methods like hand catching, cannon nets or chemical capture may be better suited to certain contexts and target species.
The choice of bird capturing technique depends on the study goals, target species, resources and desired sample size. Non-selective mass capture methods are best for getting overall population data, while more selective and targeted methods are preferred for capturing specific individuals or species for banding and detailed research. Some methods like chemical capture also raise ethical concerns that scientists must consider. Finding the right balance of practicality, selectivity and welfare impact is key to conducting effective and responsible bird capturing studies.
