A black bird is loudly, rapidly, caw-cawing in the tree outside your window. Others are flying in groups riding the air currents. Numerous black birds are eating on the ground. Are they Ravens or Crows? Sometimes they’re both or neither.
Ravens and Crows, which are abundant throughout the Bay Area, are scavengers, part of the “clean-up crew” of the bird world, eating carrion, garbage and, at times, nesting baby birds. They’re different species, both from the corvid family, genus corvus. Behavior, body structure and calls are the fastest ways to distinguish the two.
California’s Common Raven, corvus corax, is all black, and, when full grown, has a four-foot wingspan, measuring more than two feet long from head to tail. Their voice is more gravelly and deeper than Crows. Ravens stand and perch tall; more vertical than horizontal. They have large black heads, beaks, eyes, legs and feet. Everything about them is bigger and thicker than Crows. They can be surprisingly docile when raised as pets, though it’s not encouraged to keep them in captivity, and enjoy talking. They love to observe and have a wide range of sound mimicry. They hop. When flying, their tail arcs outwards in a softened “V” curve. A mnemonic: Raven has a “V” in it. They’re oftentimes seen in pairs or groups and, when flying, float on thermals and soar, with minimal wing flaps.
California’s Northwestern Crow, corvus caurinux, is, also, all black. Adults are easily half the size of a mature Raven, measuring 16 to 20 inches, almost half of which is tail. They “caw-caw”, although can mimic several other sounds too. Crows stand and perch more horizontally; their beaks look pointier, albeit still quite sturdy. All their features are black too, yet more refined.
Wild Crows and humans can form bonds of trust and friendship. When this happens, your Crow might bring you something shiny as a gift, much like they’d do for their mate in their nest. They’re social and can distinguish different humans by personality and whether they’re friend or foe. They walk and run along. When flying, the end of their tail is straight across; they rapidly flap their wings every few seconds, rather than soar. They’re oftentimes seen in groups.
Both Ravens and Crows are protected by the Federal Migratory Bird Treaty Act because they cross State lines. It’s illegal to hunt Ravens. However, some areas have an annual open hunting season for Crows from December to April, ending just as breeding and nesting seasons begin.
Birds weigh less than they appear. They have hollow bones for air flight. The best time to birdwatch is on overcast days, when reduced sun and glare allow for better viewing of silhouettes against the sky, which more easily shows flight patterns and body shape.
To hear Raven and Crow calls, as well as other birds: Audubon.org.