About 15 years ago on a cold winter afternoon, I was driving on Route 93 north in Wilmington when I noticed two hefty-looking crows on the side of the highway, feeding on a dead animal. The black birds had big, thick beaks, and looked to be nearly twice the size of your typical crow.
When I told my friend and colleague, Larry Kelts, a biologist and professor emeritus at Merrimack College, about the big crows, he said they likely weren’t crows at all. They were probably ravens.
“Ravens?” I replied. “I didn’t even know we had ravens in Massachusetts.”
Kelts explained that ravens were more common in northern New England, but sometimes showed up in Massachusetts during the winter.
Now the common raven (Corvus corax) is increasingly becoming a year-round resident and once again breeding in Massachusetts.
Ravens were persecuted by early settlers in Massachusetts and elsewhere, in part because they fed on grain, and were also believed to feed on some livestock, such as baby lambs, according to Wayne Petersen, director of Mass Audubon’s Massachusetts Important Bird Areas program. By the mid-1800s, ravens had pretty much disappeared from the state.
As ravens began their recovery in Massachusetts in the 1970s and ’80s, they visited mainly in winter, said Petersen, especially in the western part of the state.
“For many years, Quabbin Reservoir was raven central,” said Petersen. “MassWildlife, as part of their early efforts to restore bald eagles in the Commonwealth, regularly put deer carcasses on the ice for wintering eagles to feed on. This practice gave ravens a leg up as well.”
By 1990, there were at least 14 active nest sites in western Massachusetts. And from 2007 to 2011, there were 100 confirmed nestings in the state.
Ravens are now showing up in the Boston suburbs, Petersen said, and they’re doing well.
"Ravens used to like wilderness areas," said Petersen. “But now they've adapted to civilization. They're even nesting in places like college campuses, cell towers, and on the ledges of buildings."
Nesting sites in eastern Massachusetts in recent years have included quarries in Woburn and West Roxbury, as well as a cell tower in Newburyport, Petersen said. A pair of ravens nested on a fire escape at Wellesley College a few years ago, and became Internet celebrities after the college set up a raven cam website to monitor the birds and their chicks. Unfortunately, the male of the pair met an untimely end when he accidentally flew into a window.
Natural nest sites are usually on ledges of rock cliffs, or high in tall trees, according to the National Audubon Society guide to ravens, and are built with large sticks and twigs, with soft material like grass in the middle.
They typically lay four to six eggs, which hatch after about 21 days. The male feeds the female during incubation, but both parents bring food for the nestlings, which leave the nest about five to six weeks after hatching.
Although sometimes confused with their close relatives, crows, common ravens are much larger.
“They’re our largest perching bird,” said Petersen. “They’re about 24 inches long, with a wingspan of up to 53 inches. They also have more pointy wings than crows, and a wedge-shaped tail as opposed to the more rounded tail of a crow. And ravens have a huge bill, almost banana-shaped, as well as shaggy feathers on their throat.”
The American crow is about 16 to 20 inches long and has a wingspan of up to 39 inches, according to the Cornell Ornithology Lab website, allaboutbirds.org. Unlike the familiar “caw-caw-caw” sound of the crow, the common raven tends to make a deep gurgling croak.
Ravens can also soar like large hawks, Petersen said.
“They get quite high in the air and soar in circles in small groups,” said Petersen. “They’ll sometimes tumble and free fall, then open their wings and soar, more often during courtship.”
Ravens are also extremely intelligent.
“Corvids, the family of birds that includes ravens, crows, jays, and magpies, in general, are as smart as parrots,” said Petersen. “They engage in play, a hallmark of intelligence for all animals”.
For example, ravens like to play in the snow, rolling and sliding down snow-covered hillsides, said Petersen.
Ravens are also good at vocal and behavioral mimicry, another indicator of animal intelligence, and can even be taught to speak a few words, Petersen said.
Ravens have also played a role in mythology and folklore, and became a part of American literature in Edgar Allen Poe’s poem, “The Raven.” A statue of Poe and a raven was erected in Boston in 2014.
The Smithsonian National Zoo web page on ravens said they can live from 10 to 15 years in the wild.
Ravens are both predators and scavengers, and their omnivorous diet includes insects, rodents, lizards, frogs, and even the eggs and young of other birds, according to National Audubon. They regularly eat carrion and garbage as well.
Perhaps the most unusual aspect of ravens’ foraging behavior is their close association with wolves, which has led to ravens sometimes being call “wolf birds.”
Where ravens and wolves coexist, ravens will feed on the carcasses of animals that wolves kill, like elk in Yellowstone National Park in Wyoming, said Petersen.
According to Cornell, University of Vermont researcher Bernd Heinrich, who studied ravens extensively, discovered that ravens were found near wolf packs up to 99.7 percent of the time in winter at Yellowstone.
But the wolf-raven symbiotic relationship doesn’t end there. It is thought that ravens might actually lead wolves to potential prey on occasion.
According to the Cornell website, “He [Heinrich] notes instances in his Yellowstone studies in which ravens located injured elk and called raucously, attracting the attention of a local wolf pack to an easy kill. Could it be that wolves and ravens are hunting partners who share the spoils?”
An intriguing possibility, and one that adds to the legend and mystery of the “wolf bird.”
Don Lyman is a biologist, freelance science journalist, and hospital pharmacist who lives north of Boston. Send your questions about nature and wildlife in the suburbs to firstname.lastname@example.org.