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| A crow and a raven, respectively. photo by Gerrett Lau |
But your confusion is understandable, after all they are both sleek black birds that you see everywhere and they are very closely related; both belong to the genus Corvus. Many species of Corvus exist throughout the U.S. but on the west coast you are probably most familiar with: The American Crow (Corvus brachyrhynchos) and the common raven (Corvus corax) [1][2].
The American Crow is a highly sociable bird and can form enormous flocks (lovingly known as "murders") that can include over a million individuals. The American Crow is significantly smaller than the common raven but, not to be outdone, it uses its larger numbers for success in both breeding and hunting.
Crows are monogamous but often form large family groups where older offspring help parents take care of the new chicks; sometimes staying with the parents for many years. 15 birds to a nest is not uncommon [3][4]. Each individual helps provide food and care for the family, and they work as a team to acquire food. Teams of cunning crows have been known to distract predators while another crow sneaks in from behind to steal the predator's hard-earned meal [5]. This is all to say that if the black bird you see is one just one in a flock, you can be fairly certain it is a crow.
Ravens on the other-hand live a more solitary life. They can form mating pairs, but it is rare to see more than two together [5]. But like crows the ravens can work together to get prey and are extremely clever at finding food, but their size is less of a factor. Common ravens are the largest of all American corvids, and its one of the primary ways they can be distinguished. Ravens also prefer woodlands, open-landscapes, and mountainous areas to cities and towns. Ravens are not uncommon in urban areas, but they do not seem to have the affinity for human settlement that crows do [6].
But like everything in nature, exceptions are all to common. Common ravens can occasionally be seen in large flocks in the cities, and crows can be seen all alone in the forest. When you are unsure, beaks and tails are tell-tail signs (see what I did there?). Ravens sport a wedge-shaped tail and a longer, heftier beak. They also sport distinctive neck plumage when they call. This is opposed to the squarer tail and smaller, rounder beak of the American Crow [7][8]. Still unsure? Look for it's flight pattern. If it is performing acrobatic tricks, its probably a raven.
While crows flap almost continuously in flight, ravens are known to glide for long periods and take this time to show off mid-air stunts. famous for their aerial acrobatics, a raven was even recorded flying upside down for more than half a mile. Quick dives up and down, somersaults, and even dropping and catching objects in mid-flight are common sights if you pay attention when ravens fly by [5].
Their calls are also distinctive, and fitting to their body-type. The smaller American Crow's calls are higher pitched, and you can often hear many of them together. Their calls are probably the most familiar to you, the traditional caw-caw [9]. Common ravens have a deeper, harsher voice, and often can be heard alone [10]. But before you identify them on sound alone, you should know that both crows and ravens produce a variety of sounds and are notorious imitators; even mimicking human speech.
Up until now I have been hesitant about writing a crow or raven post. Not because their isn't enough to say about them, but because there is an intimidating amount. Intelligence on par or over some primates, these birds are extraordinary, and now that you know the difference you can look forward much more extensive posts on them coming soon. In the mean time let me know what animals you want know the difference between and keep up with animal facts and science news on my Twitter: @everydayanimal.
More information on the differences between crows and ravens:
http://birdnote.org/show/ravens-and-crows-who-who
http://www.youtube.com/watch?v=guBwMUAWAJI
http://www.allaboutbirds.org/page.aspx?pid=2501
Sources:
[1] http://www.allaboutbirds.org/guide/American_Crow/lifehistory
[2] http://www.allaboutbirds.org/guide/common_raven/id
[3] http://www.birdweb.org/birdweb/bird/american_crow
[4] http://www.news.cornell.edu/chronicle/97/4.10.97/crow.html
[5] http://www.allaboutbirds.org/guide/common_raven/lifehistory#at_nesting
[6] http://www.birdweb.org/birdweb/bird/common_raven
[7] http://animals.nationalgeographic.com/animals/birding/common-raven/
[8] http://animals.nationalgeographic.com/animals/birding/american-crow/
[9] http://www.allaboutbirds.org/guide/American_Crow/sounds
[10] http://www.allaboutbirds.org/guide/common_raven/sounds
Photo by Garrett Lau from:
http://birdnote.org/show/ravens-and-crows-who-who
