Ancient Technique Allows 21st-Century Hawk to Soar

Article and Photos by Pamela Hartmann

A hawk's survival requires an exquisite ability to soar and maneuver in order to hunt. This is especially true of Red-shouldered Hawks, explains Claudia Duckworth, of Pacific Wildlife Care. They are "masters of maneuverability," often chasing prey (usually small birds) through dense forest. A hawk with seriously damaged tail feathers is not able to do this.

On May 24, 2014, a Red-shouldered Hawk with a fractured wing was brought to the PWC Morro Bay Rehabilitation Center. On his medical chart, he was identified as RSHA 766. After PWC veterinarian Dr. Shannon Riggs set the broken wing, the bird spent almost four months in recovery. Of necessity, he was confined to a small cage. In a larger space, he would have attempted to fly, thereby re-injuring his broken wing. As sometimes happens, restriction to the small area led to broken tail feathers that were "kind of a disaster," as Riggs describes them. Even the tail-guard placed on the bird was not sufficient to prevent this damage.

The wing healed, and through August and early September, the bird was creanced—exercised multiple times on a 150-foot line to strengthen him in preparation for release back to the wild. With a healed wing and strong muscles, he regained his ability to fly fast without tiring, but only in a straight line. The broken tail feathers (and several on one wing) did not allow for precise maneuvers.

The tail feathers are "like a rudder on a plane or boat," Riggs says, and without them, or with only tattered feathers, soaring and maneuvering are not possible. Eventually, these mangled feathers would molt on their own, and new ones would grow, but this would take a long time, and the goal at PWC is to release healthy wild animals as soon as is practicable. Nobody wanted to keep #766 confined any longer than necessary.

The solution to this problem is a procedure called "imping," a centuries-old technique used by falconers to attach donor feathers onto a bird's tail or wings. "Falconers," Duckworth explains, "are fanatics about feathers. They won't fly a bird with even one broken feather."

But imping is not taught in veterinary school. Riggs ended up learning it from a U.C. Davis veterinarian who was also a falconer.

On a sultry September afternoon, in the surgery room at Pacific Wildlife Care, Riggs sets out the equipment to imp Red-shouldered Hawk #766. Jeanette Stone, also of PWC, brings him in, wrapped in a towel that covers his eyes to minimize stress. She soon has him anaesthetized on the operating table. Anesthesia is an advantage that PWC has over falconers. Without access to anesthesia, a falconer must rely on a strong assistant to physically restrain the bird during the process.

To Riggs' right is a set of perfect donor feathers. She harvests these from deceased birds, catalogues them, and stores them in a feather repository in the Center's walk-in freezer. The choice of feathers must be precise. Each imped feather is from a bird of the same species, size, and age. Usually, the gender must also be the same since gender affects size, with female raptors being larger than males. The set of feathers for each wing is numbered 1 to 10. The twelve tail feathers are also numbered, 1 to 6 on each side. Because of a shortage of Red-shouldered Hawk feathers, Riggs had to turn to Ojai Raptor Center for a set of feathers for the imping of #766.

Each feather is attached to a bamboo skewer, which Riggs cuts to the right length just before inserting it in the shaft of the bird's own, broken feather. She uses a cauterizing tool to make a clean cut in both the skewer and the original shaft. Jeanette Stone, carefully monitoring the anaesthetized bird and opening the valve every 5-10 seconds to basically breathe for the bird, says the cauterizing smell reminds her of her father, "when he used to make arrows."

Bamboo skewers make an almost—but not quite—perfect fit. Riggs inserts one, finds it's too tight, and shaves it down with a scalpel blade until it slides smoothly about an inch or so into the shaft. She then applies a drop of 5-Minute Epoxy to secure it, places a rectangle of cardboard ("business cards work well," Stone says) between this feather and the next, and picks up another donor feather to repeat the process.

When she is finished, she spreads out the tail to display the perfect "new" feathers. The tail is a thing of beauty. Imping, Riggs says, is "one of the most fun things to do. Instant gratification."

Perhaps imping is fun for Riggs, but Claudia Duckworth cautions, "Until you do it, you don't know how difficult it is." Riggs makes it look easy. Before she brought her skills to PWC in 2013, there was no systematic way to deal with broken feathers on birds of prey. Often, Duckworth says, they "released birds with missing feathers . . . and hoped they could cope," or they took birds to Ojai Raptor Center for imping. At one point, Duckworth went to a workshop on imping at the Minnesota Raptor Center, but "learning it in a class and doing it are two different things."

The devil, she found, is truly in the details. As with so much else in caring for injured wildlife, a lot can go wrong. Several years ago, before Riggs' arrival at PWC, Duckworth and Stone attempted to imp feathers on a Red-tailed Hawk. Their first mistake was not realizing they needed bamboo skewers. They tried matchsticks and then metal and only by trial and error ended up with bamboo. Then, because they cut the shafts with scissors instead of cauterizing them, the shafts split, and feathers were everywhere on the ground the next day. Then they discovered the connecting material (they tried Superglue at first) didn't work. They also came to appreciate the importance of having every feather at the exact right angle because, as Duckworth explains, the bird has muscles to control each feather in a certain way. Finally, on the third attempt, the donor feathers held. Success! But, Duckworth says, "I think none of us wanted to do it again."

Then Dr. Shannon Riggs was hired full-time by Pacific Wildlife Care, to everyone's great relief and the good fortune of Red-shouldered Hawk #766. Two days after imping, he was creanced one last time by Virginia Flaherty, who noted in his medical record, "The bird flew beautifully. . . . Ready to release," which is what happened on September 17, in Atascadero, an event made possible by the PWC facilities, donor feathers, Dr. Riggs' expertise, and centuries of knowledge received from falconers.

Preparing the Tail Feather for Imping

Inserting New Feather Into the Shaft

Halfway Through the Procedure

Tail Imping Completed (All 12 Feathers)

For more information on Pacific Wildlife Care, a 501 (c)3 non-profit organization,
or to volunteer or make a donation, go to the website: Pacific Wildlife Care

If you find an injured wild animal, call the PWC Hotline (805-543-9453).