During the winter, American Crows congregate at night in large communal roosts. These roosts range in size from a few hundred, several thousand, or even up to one million crows.
The winter roosts of some American Crows have been located in the same area for well over 100 years.
In recent decades, some American Crows have moved their winter roosts out of rural areas and into cities. Their noise and mess have created numerous conflicts with residents in these urban areas.
Just as a flock of quail is called a “covey,” a group of crows is called a “murder.” Unlike most American Crows that maintain a year-round territory, the majority of crows that nest in Canada leave their territories and migrate south to the United States for the winter.
Since American Crows do not breed until they are between two to four years old, they often stay with their parents and help them raise the young of following years. Family groups may include over a dozen individuals from five different years.
Birdwatchers know to listen for American Crows raising the alarm when predators are discovered. They vigorously mob owls and can tip off their location to alert birders for a closer look.
Crows themselves are often mobbed by smaller birds, especially kingbirds and Red-winged Blackbirds.
The loss of American Crows to the West Nile virus has been the highest of any North American bird species. They die within a week of exposure and very few appear to be able to survive once infected.
American Crows are commonly seen feeding on road-killed animals but carrion is only a very small part of its diet. The bill is not strong enough to break through the skin of most animals and they can only feed on partially decomposed or previously opened carcasses.
Shiny objects seem to fascinate crows. They have been known to fly off with bits of glass, rings, keys, and foil.
Crows can imitate a large number of sounds including whistles, cats, machines and the human voice.
The oldest known American Crow in the wild was recorded to be almost 15 years old.
The Fish Crow, found all year-round in coastal areas of the southern and eastern United States, opens mollusks for eating by continuously dropping them on a hard surface to crack them apart.
The best way to identify Fish Crows is by their short nasal calls car or cuh-cuh as opposed to the caw of the American Crow.
Like a stunt pilot at an air show, the Common Raven often performs rolls and somersaults while flying. They have even been known to fly upside down for over a half a mile.
Common Ravens will often “commute” up to 55 miles a day to reach good sources of food.
Ravens are well adapted to cold weather. Thick soles on their feet and dense plumage allow them to maintain a normal metabolism until temperatures drop below -4°F. Only then does their metabolism need to increase to generate extra body heat.
Common Raven pairs will try to exclude all other ravens from their year-round territories. When a carcass is found during the winter, young ravens will call other ravens into the area to help them overwhelm the local resident pair. This distracts the “rightful” owners and allows them all to steal a meal.
The Common Raven often lines its nest with sheep wool and will cover its eggs with the wool when it leaves its nest.
Common Ravens are curious and have been known to peck holes in airplane wings and to steal balls off of golf courses.
The oldest known Common Raven in the wild was recorded to be over 13 years old.