Wild Things: Common Raven (Corvus corax)

Photo by James Taulman.

The common raven is a large, all-black, thick-billed bird measuring about 25 inches in length with a wingspan of over 4 feet, and weighing 2-3 pounds. The feathers show a bluish or purple sheen in reflected sunlight. They may live up to 21 years in the wild, one of the longest lived of the passerine (perching) birds. Ravens mate for life and stake out territories. They are found in a variety of habitats, from forests to deserts and prairies, even in the arctic tundra, provided that elevated cliffs or other vertical features are available for nesting. They are common in the western United States and Canada, but absent in the central plains, the southern states, and eastern seaboard. 

In diet ravens are omnivorous, eating a wide variety of live foods and carrion, such as grains, fruits and berries, insects, small vertebrate animals, birds and eggs, and human food wastes. Juveniles have been observed to call loudly at a food cache, such as a mammal carcass, attracting other ravens to the site.

Ravens originated in Europe and are believed to have come to North America across the land bridge in the Bering Sea some 2 million years ago. They are distinguished from the smaller crow by the larger size and more massive bill, flared or shaggy throat feathers, and more stable flying style. One can often see ravens soaring in thermals, where they can gain altitude without flapping.

Ravens pair for life and defend a territory with good nesting and food resources. They have a wide repertoire of vocalizations and can mimic many other sounds in the environment. The nest may be in a tree or cliff bank or on a utility pole or abandoned building and is constructed using large twigs and roots, held together with mud and lined with softer materials. The female incubates the eggs alone for about 3 weeks and the young fledge about 40 days after hatching. These large aggressive birds have few natural predators, but large raptors such as hawks and eagles may prey on eggs or juveniles in the nest. Coyotes and large wild cats are also known predators. While ravens may live as long as 40 years in captivity, the oldest known wild banded raven died after 23 years.

The high level of intelligence possessed by ravens is well documented. Ravens have been found to be able to share information about a food source with others and then to later lead that group of birds to it. The only other species known to communicate information about distant resources to others are ants, bees, and humans.

The problem-solving ability of ravens is also well documented and can involve the imaginative manipulation of novel objects to overcome barriers in order to reach food items. Ravens are also known to watch another raven when it buries surplus food and then to go and raid that cache. Juveniles are attracted to colorful, shiny objects, which they may cache with food items.

Another important indication of intelligence and inventiveness is casual play behavior, seen in very few birds. The exploratory behavior involved in play is thought to be an indication of an imaginative mental depth and is normally associated primarily with mammals. Ravens have been observed sliding down snow slopes, apparently for no practical purpose but just enjoyment. I recently watched a raven chasing a jackrabbit, repeatedly diving on it as the rabbit hopped away. The bird perched briefly between bouts and then again flew at the rabbit until it ran. The raven was clearly not attacking the rabbit in a predatory way.

Ravens can become pests and may reduce crop yields or pester livestock. The Audubon Society reports that the range of the raven is stable in all western states and is only undergoing reduction in the northeast and Great Lake states.

Photos were taken on Highway 41 south of Moriarty, and in Edgewood. Camera is Nikon P900. James Taulman is a semi-retired research wildlife biologist, having worked with the U.S. Forest Service research branch and taught zoology, ecology, and other courses in several university positions. He is currently living in the East Mountains, and explores natural areas observing native wildlife and conducting independent research projects.