Bird of the Month March 2019

Common Raven

Corvus corax

If you see a large, all black bird, you are likely looking at a Common Raven. They are nearly as large as a red-tailed hawk, have a huge chisel-like black bill, black eyes and gray feet. They soar like eagles and can fly long distances.

Behavior and Habitat

Ravens utilize a wide variety of habitats from montane forest to desert and just about everything in-between. They have adapted well to humans and are often found in close association with agriculture, ranching and just about anyplace humans gather with potential food items, including trash.

Ravens will eat just about anything organic and are capable hunters. They most often prey on small or young critters but any vulnerable animal (such as nesting Great Blue Herons and pigeons) is fair game. Elsewhere, they have been implicated in population declines of endangered species such as Least Terns, Marbled Murrelets and desert tortoises. In the Intermountain West, Common Ravens are significant predators on Greater Sage-grouse eggs and young.

Common Raven couples usually stay together throughout the year, not just during nesting. They build large stick nests up to six feet in diameter and two feet tall, often in the fork of a tree, on a rooftop or on a cross-member of a power pole. Nests are often used from year to year but not necessarily by the same pair that built it. There they raise from 3-7 youngsters.

Common Ravens are members of the Corvidae family which includes crows, jays and magpies. These are all intelligent birds able to problem solve and work cooperatively. This intelligence often lands them in “hot water”. With a little work, Common Ravens have learned how to open lunch pails, remove lids, open snowmobile “trunks”, and cooperatively hunt together with one bird distracting an incubating adult while the other steals the eggs or chicks.

 

Similar Species

You are most likely to mistake a Common Raven for an American Crow on Camas NWR. Crows are also jet black, but crows are about half the size of ravens and have a smaller less imposing bill. Ravens also have scruffy feathers around the neck that crows do not have. More than that, behavior is often the key. Ravens are most commonly seen singly or in pairs, less often in groups unless there is an attractive food source. On the other hand, crows are most commonly found in flocks, seldom solo.

Cool Facts from: All About Birds.org

Common Ravens are long-lived species. The oldest wild raven on record was over 22 years old.

Common Ravens can mimic the calls of other bird species. When raised in captivity, they can even imitate human words; one Common Raven raised from birth was taught to mimic the word “nevermore.”

The Common Raven is an acrobatic flier, often doing rolls and somersaults in the air. One bird was seen flying upside down for more than a half-mile. Young birds are fond of playing games with sticks, repeatedly dropping them, then diving to catch them in midair.

Breeding pairs of Common Ravens hold territories and try to exclude all other ravens throughout the year. In winter, young ravens finding a carcass will call other ravens to the prize. They apparently do this to overwhelm the local territory owners by force of numbers to gain access to the food.

They also use their intellect to put together cause and effect. A study in Wyoming discovered that during hunting season, the sound of a gunshot draws ravens in to investigate a presumed carcass, whereas the birds ignore sounds that are just as loud but harmless, such as an airhorn or a car door slamming.

When and where found at Camas NWR

Look for Common Ravens just about anywhere on or off the refuge. They can commonly be found scavenging road-killed animals and following farm equipment such as discs and plows that disturbs the soil and expose prey items.

Conservation

“Common Raven populations increased across the continent between 1966 and 2014, according to the North American Breeding Bird Survey. Partners in Flight estimates their global breeding population to be 20 million with 18% living in Canada, 9% in the U.S., and 3% in Mexico. They rate a 6 out of 20 on the Continental Concern Score and are not on the 2014 State of the Birds Watch List. Common Ravens tend to do well around people, profiting from the garbage, crops, irrigation, and roadkill that accompany us. Their numbers are generally stable or rising in western North America. As eastern forests were cut down in the nineteenth and twentieth centuries ravens disappeared from most of eastern North America, but they are beginning to return to the Northeast as forest cover regenerates. In many situations ravens are unwelcome: they have been shot at, poisoned, or harassed in attempts to preserve crops (and occasionally livestock such as lambs). Ravens sometimes prey on threatened species, including Least Terns, Marbled Murrelets, and desert tortoises, and wildlife biologists have spent a lot of effort and ingenuity in trying to thwart ravens to help those species, with mixed success.” www.allaboutbirds.org/guide/Common_raven/lifehistory

Text by Terry Thomas. Source: https://www.allaboutbirds.org

Photo by Terry Thomas.