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To trap an eagle

Eagle trapping is like fishing, Bryan Watts says, in that it involves a variety of techniques and a whole lot of patience. Watts, Libby Mojica and the Center for Conservation Biology team use three methods to trap eagles.

  1. Baited water snares. A dead catfish is stuffed with styrofoam and rigged in a monofilament loop anchored in open water. When the eagle grabs the floating bait, the loop closes around its talons.
  2. Padded leg-hold traps. Raccoon-sized traps are customized with padded grips and weaker springs designed to grab and hold-but not injure-a raptor. They're baited with fish.
  3. Rocket nets. Eagles are attracted to a nice ripe deer carcass, then caught under a 30x60-foot net fired from a device 50 feet away using blank howitzer rounds.

The first two techniques are passive methods and the leg-hold traps tend to catch more vultures than bald eagles. The rocket nets are effective and selective, but require a crew to sit quietly in a blind for hours, waiting for a bird to descend to the bait before they pull the trigger. Mojica says the rocket netting is only used in the winter, because eagles won't key in on the deer bait until the cold weather makes fish, their preferred food, scarce.

"It is like fishing," Watts said. "Eagles are hard to trap. They are incredibly wary birds and they will watch a bait for hours to see if there's anything suspicious. They'll sit up there on their roosts and watch the crows come in, then the vultures, before they decide that it might be all right to come down and have a look. Sometimes you sit out there all day and never get a bird. You're just waiting for that big strike."

The eagle researchers are supplied with bait by cooperative biologists and game wardens in the area. Biologists from the Virginia Department of Game and Inland Fisheries shock up catfish, while army game wardens at Aberdeen maintain a cache of fresh road-kill deer. When a bald eagle is snared or netted, the action becomes less like fishing and more like a raptor rodeo, the researchers hustling to subdue and secure the eagle without harm to the bird or themselves. "Oh, I've been bitten a time or two," Mojica said. "Bryan has too. It's not bad; more like a bruise than anything."

Watts explained that the crew tries to get a hood on the eagle as soon as possible. Once visual stimuli are shut down, the eagle settles down, allowing the researchers to secure its wings and talons. (Ace bandages come in handy to immobilize the birds.) The captured bird is fitted with its GPS transmitter and released. The hood is the last restraint removed. "When you take that hood off, it instantly becomes a different bird," Watts says.