Rocking J Ranch

Eagles are one of the most violent and most aggressive predators we have to watch for here!
We typically have bald eagles 🦅instead of golden eagles, but they are still a threat.
They are also a federally protected species and can’t be dealt with in the same manner as most predators. We utilize dogs 🐶 who deter them from landing on our property in conjunction with protective mothers and vigorous newborns, and it has worked well so far!

In 2019, Alaska Department of Fish and Game biologists found dead muskox calves on the tundra, sent them to Fairbanks for autopsy, and a wildlife veterinarian confirmed that a golden eagle had crushed one calf's skull with its talons and punctured another's lung from above the spine.

Brynn Parr, one of the ADF&G biologists working the muskox research program, described the findings plainly. They found the carcasses and shipped them to Fairbanks. Dr. Kimberlee Beckmen, the department's wildlife veterinarian, skinned them out and did a full forensic investigation. She found exact talon puncture marks. One eagle had driven its talons into a calf's back above the spine and punched through the rib cage into a lung. Another had attacked the face and crushed the skull. There were no bite marks, no tooth punctures, no sign of a terrestrial predator. The weapon was a foot.

A golden eagle weighs roughly ten to fourteen pounds. A muskox calf at birth weighs about twenty to twenty-five pounds and gains weight fast. Within days, a calf can outrun a person. By July, it can weigh over thirty pounds. Eagles have been documented killing calves that size and older. The attack method is not a dive and release. It is a sustained grip. The eagle comes in low and fast, locks its talons around the calf's body, and does not let go. The talons are curved, thick, and built to close around a spine. In ungulate kills documented across North America, the usual cause of death is massive internal hemorrhage from a punctured aorta or lung collapse from talons driven through the rib cage.

Golden eagles are the most powerful avian predator in North America and among the most powerful on earth. They hunt primarily rabbits, hares, ground squirrels, and marmots. That is what most people know. What most people do not know is the other end of the prey list. Golden eagles have been documented killing adult pronghorn antelope, adult mule deer, caribou calves, bighorn sheep lambs, coyotes, bobcats, and foxes. In 2005, a paper in the Western North American Naturalist reported a confirmed golden eagle kill of a sixty-pound pronghorn. The necropsy found no bite marks on the carcass, only talon punctures consistent with an eagle's grip, and a fractured cervical vertebra. In 2013, a camera trap set for Siberian tigers in the Russian Far East captured images of a golden eagle attacking and killing a sika deer weighing between eighty-eight and a hundred pounds. The researchers had been studying tiger kills for eleven years and had never seen evidence of eagle predation on deer until the camera caught it happening.

The kill technique is called a low flight with sustained grip attack. The eagle does not strike and fly away like a falcon. It lands on the animal, grips, and stays. It uses its wings for balance, riding the animal as it runs, and drives its talons deeper until the prey collapses from blood loss or shock. The attack can last anywhere from a few seconds to fifteen minutes. Experienced eagles develop personal hunting strategies over lifespans that can reach twenty-five to thirty years.

ADF&G biologist Ken Whitten, who studied golden eagles on the Arctic Slope, noted that muskox calves are most vulnerable in their first three to four days. After that, they are alert and fast. But eagles are opportunistic, and calves can still be taken well into summer. The muskox's famous defensive formation, adults circling with horns out and calves in the center, works against wolves. It does not work against something that comes from above.

Beckmen, who has been ADF&G's wildlife veterinarian for decades and has performed necropsies on everything from moose to wolves to sea otters, described her work as being like a medical examiner. The investigative work is the part she finds satisfying. When you can figure out what happened, she said, that is the reward. In 2019, what happened to two muskox calves was a bird.

Source: Alaska Department of Fish and Game / Kerley and Slaght (2013), Journal of Raptor Research / Western North American Naturalist (2005).