Predators are not always four-legged: Ravens are known to prey on livestock

Predators are one of the challenges producers face when raising livestock, and many ranchers are all too familiar with coyotes, wolves, cougars and bears.  

In some situations, however, cattle are also killed by birds – primarily ravens. These big birds are much larger than crows, about the size of a red-tailed hawk, have a wingspan of 3.5 to four feet and are 24 to 27 inches long from head to tail. Crows are smaller, with a wingspan of about 2.5 feet and are about 17 inches long.

Livestock Protection Program Coordinator for British Columbia Cattlemen’s Association Cam Hill shared Livestock Protection Program verifiers are trained to verify livestock kills by wolves, coyotes, bears or cougars. 

“We are also finding an increase in bird kills, generally ravens, although eagles are sometimes accused as well,” Hill said. “This is the fourth year for me as program coordinator and when I first started, I went through the records and found we’d averaged seven raven losses per year where we verified and paid compensation on. Then we had 37 raven losses in just one year. I did some research and found articles from three Canadian provinces, one western U.S. state and Sweden which shared about losses to ravens,” said Hill.

“In some areas of British Columbia, the wildlife populations have declined,” Hill continued. “There are fewer moose, and in some areas, fewer elk and deer. My theory is with fewer wild ungulates, the ravens may be looking for other food sources.”

Hill explains the birds are very intelligent and may be seeking other options, noting, “If there are fewer wolf kills of wild ungulates, ravens don’t have as much opportunity to scavenge, and are turning to cattle.”

Hill thinks this is a learned behavior. If a farm or ranch has a problem with ravens, they generally have multiple problems, though it may be only one bird doing the damage. 

Predatory behavior

Ravens are larger than crows or magpies, and cattle seem to have an instinctive fear of large predatory birds flying over the herd.  

When calves are young, a group of ravens flying over the calving ground will upset cows as much as if there were coyotes or wolves coming through; the cows bawl and try to look up, and the whole herd may be running and bawling, sometimes trampling young calves.

“Ravens are quick and deadly,” Hill said. “One producer was watching a cow calving on a grassy hillside when he saw a raven land near the cow. The calf was still in the birth canal. The raven hopped onto the calf, and all it takes is one quick peck to the eye. The rancher didn’t realize at first what had happened, but as soon as the calf was fully born, he drove up to the pair and found the calf was dead and its eye was gone.”

“The year I examined 37 cases regarding calves and lambs which were killed by ravens, it was almost always the same scenario; the eyes, rear vents, anus, navel and soles of the feet were pecked away,” Hill continued. “Often all of those sites were pecked, or sometimes just a couple, but in 95 percent of cases the eye was the first strike area.”  

A deep peck does a lot of damage; it can damage the brain, but also causes a lot of bleeding. The calf can bleed out in a short time.

Recognizing raven attacks

Even though the cow generally tries to protect her newborn, she is helpless to do so while she is still down and in labor – and the birds take advantage of this.

“Some of the producers I talked to had not yet recognized this as a problem and were frustrated these calves were dead,” Hill said. “We know if a calf is born dead or dies soon after birth from other causes, birds will peck out their eyes. So, this has to be part of the verification process.”

“Once a person has seen it, however, they can tell right away the calf was still alive and died from an eye strike because they bleed profusely from the eye socket,” Hill said. “There is blood all over the side of the face. Sometimes the cow will lick blood off, but the eye socket will have visible damage.”

“I think producers are starting to recognize ravens can be predators and kill calves,” he explained. “This happens most commonly in newborns – while the calves are being born and when the cow can’t defend them – and with very young calves.” 

Hill notes eagles sometimes hang around and feed on carcasses following attacks by ravens, and ranchers sometimes blame eagles for the deaths rather than ravens.  

“In my opinion, bald eagles are getting a bum rap,” Hill said. “They are generally just scavengers, whereas golden eagles are the hunters and predators. Bald eagles are more timid; if the animal moves, they will fly away because they are scared of it.” 

Golden eagles are much more aggressive and will pick up young lambs and carry them off.

“Every year we have a few cases where producers think eagles were the cause of a problem, but I think ravens are the primary bird predators,” concluded Hill.

Heather Smith Thomas is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to roundup@ wylr.net.