Capturing wild birds requires careful planning and preparation to ensure the safety and well-being of the birds. There are several techniques used by ornithologists, bird banders, and other researchers to temporarily restrain birds for study. The appropriate methods depend on the species, habitat, research goals, and other factors.
Reasons for Capturing Wild Birds
There are a variety of scientific and conservation reasons for capturing wild birds. Some of the most common include:
- Banding or ringing birds to track migration patterns and survival rates
- Collecting biological samples such as blood, feathers, or swabs
- Measuring morphological features like wingspan and weight for research
- Attaching tracking devices to study movement, habitat use, or behavior
- Translocating rare species away from threats or to establish new populations
- Temporary removal of nuisance birds or control of overpopulated species
Ringing or banding birds enables individual identification when they are recaptured or found deceased. Analyzing banding data helps determine migration timing and routes, lifespan and survival rates, population sizes, and more. Modern tracking technology like GPS tags and geolocators provide even finer-scale movement data when affixed to wild birds.
Permits and Regulations
Capturing and handling migratory birds is tightly regulated in most countries. Depending on the region, specific permits may be required for:
- Using capture methods like mist nets, traps, cannon nets, etc.
- Banding or attaching markers/transmitters to birds
- Taking blood samples or other biological materials
- Transporting and temporarily holding wild birds
- Releasing birds at a location different than capture site
Permit conditions help ensure humane treatment and disturbance is minimized. Personnel handling birds also require specialized training on proper techniques. Even using audio lures like bird calls or imitating them requires permits in some jurisdictions. It is essential to research and comply with all relevant regulations before capturing wild birds.
Pre-Capture Planning
Successful and ethical bird capturing requires careful planning before any contact with birds. Key steps include:
- Select suitable and effective capture methods for target species.
- Scout sites to identify areas of frequent bird activity.
- Assess potential hazards and risks like weather, terrain, or predators.
- Determine optimal timeframes based on season, time of day, and conditions.
- Have all necessary equipment, data forms, and processing stations ready.
- Train personnel thoroughly on responsibilities, tasks, and bird handling.
- Obtain land access permission and all required collection permits.
Planning the data collection and bird processing workflow is also important. Steps should minimize time from capture to release. Having teams assigned to extract each bird from nets, take samples, band, measure, and record data helps streamline this. Test runs may help refine methods and equipment.
Passive Capture Techniques
Some of the main passive techniques for catching wild birds include:
Mist Nets
Fine, nearly invisible nets are erected between poles and stretched tight, usually in areas of known bird activity. Birds fly into the nets and become gently entangled. Mesh sizes vary depending on target species – smaller for songbirds and larger for waterfowl or birds of prey. Regular monitoring and rapid extraction is vital to avoid injury and distress.
Cannon/Rocket Nets
Circular nets with weights along edges are launched high-speed over flocks using small detonation charges. A site is baited to concentrate target species before net launch. Skillful coordination ensures birds are enclosed cleanly within the circumference and quickly gathered.
Drop/Dip Nets
Small handheld nets are used to quickly lower over individual roosting or stationary birds by researchers. This is often used for owls, seabirds, and other less mobile species. It requires stealth and precise timing but minimizes stress.
Walk-in Traps
Funnel-shaped enclosures lead birds into a central chamber for containment. Bait attracts them through the funnels, which prevent escape. One-way openings allow entry but not exit. Traps are monitored constantly when open and birds promptly removed.
Nest Boxes/Platform Traps
Artificial nest cavities can allow access to cavity and platform nesting species like ducks, owls, falcons or vultures. Bird entry openings are monitored and temporarily blocked once occupied to permit capture and banding of residents.
Active Capture Techniques
More disruptive but direct active techniques are also employed for capturing certain wild birds, including:
Net Guns
Large specialized nets are propelled via explosive charges from guns or rockets mounted on vehicles or boats. Targeted birds are enveloped at a distance while in flight over open areas. Requires extensive training for safe and humane use.
Night Lighting
Bright spotlights temporarily disorient nocturnal species like owls, allowing researchers to approach and safely net them. Appropriate eyewear protects sensitive eyes from the intense lighting.
Drive Trapping
Groups of volunteers line up and walk through fields flushing ground-nesting birds like gamebirds or waders toward nets stretched between poles. Used for species in open habitats that avoid close approach.
Chemical Immobilization
Sedatives administered via darts or injections can be used to capture rare, dangerous, or highly mobile species. Experts required to calculate dosages and minimize risks. Strict protocols and permits mandatory.
Bird Handling and Banding
Once captured, wild birds require specialized handling to avoid injury, excess stress, overheating, and other risks. Key guidelines include:
- Extract birds from nets or traps as quickly as possible – within 30 minutes maximum.
- Minimize restraint time – process and release each bird swiftly.
- Handle only one bird at a time and keep in darkened bags/boxes when waiting.
- Restrain body gently but firmly, supporting the weight of larger birds.
- Use appropriate band sizes – loose enough to move freely on leg or wing.
- Take samples and gather data rapidly and methodically.
- Monitor birds for signs of distress like heavy panting or lethargy.
- Keep shaded and cooler on hot days to avoid overheating.
- Release at original capture site once fully recovered from handling.
Proper training on securely holding species of different sizes and types is critical. Using appropriate banding pliers and mastering techniques for attaching marker safely and correctly takes practice under guidance of experienced bird banders.
Special Considerations for Waterbirds
Waterbirds like seabirds, waterfowl, and wetland species require some unique capture and handling methods, including:
- Use floating mist nets, dip nets, and small canon nets for swimming/diving birds.
- Noose carpets on breeding colonies allow controlled restraint.
- Handle with extra care to avoid waterlogging plumage and hyperthermia risks.
- Assess flight ability after handling before release – dry thoroughly if needed.
- Select marker types suitable for wet environments.
- Use boats/floating blinds for access to islands/colonies with sensitive birds.
Molting waterbirds are especially vulnerable when replacing flight feathers. Restraint, handling, and release requires particular care during this flightless period for them.
Raptor Capture and Handling
With sharp talons and beaks, birds of prey like eagles, hawks, falcons, and owls pose unique challenges:
- Thick welder’s gloves essential for handler safety.
- Individual species hoods used to keep birds calm and reduce stress.
- Avoid injury to growing blood feathers in young birds.
- Assess foot and eye condition carefully – treat any injuries.
- Specialist equipment needed for climbing nests on cliffs or tall trees.
- Leather leg jesses, tracker backpacks, or Teflon ribbon bands used for tags.
Ensuring large raptors regain flight ability post-release is crucial. Supervise takeoff or consider short-term captive support if required. Specially trained falcons may help capture free flying target individuals via the pursuit and entanglement method.
Post-Release Monitoring
After releasing birds, continue monitoring and take any necessary actions:
- Watch carefully for any signs of impaired flight,injury, or disorientation.
- Have net handlers standing by to recapture if needed.
- If problems evident, provide safe containment for recovery.
- Check release site is safe from predators before birds depart.
- When climbing to retrieve mist nets, observe bird movements nearby.
- Record condition, any complications, and time until out of sight.
Use radio or satellite tags to remotely track post-release activity when possible. Maintain detailed records of captures and any issues to improve methodology.
Essential Equipment
Having proper equipment for each capture technique, handling, and data collection is vital. This may include:
Capture | Handling | Processing |
---|---|---|
Mist nets and poles | Restraint bags/tubes | Banding pliers |
Cannon/rocket nets | Thick gloves | Bands/markers |
Audio lures | Hoods/blindfolds | notebooks |
Box/funnel traps | Measuring rulers | Scales |
Net launchers | Holding boxes | sampling kits |
Night lighting rigs | Misting bottles | Calipers |
Boats/blinds | First aid supplies | DNA samplers |
Portable folding tables, chairs, field computers, and other equipment to efficiently process birds are also important. Having backups of essential gear helps keep operations running smoothly even if something breaks or fails.
Conclusion
When properly executed, capturing wild birds only briefly disturbs them while providing invaluable scientific insights. Responsible practices focused on safety and welfare are essential. The appropriate technique depends on the species, habitat, research goals, and regulations. Passive methods like mist nets minimize stress. More disruptive active approaches require extra care and training. Meticulous handling and rapid, streamlined processing reduces impacts. With careful planning, preparation, and technique, wild birds can be captured and released with no lasting harm.