Wednesday, October 7, 2015

Crowing about Crows

The American Crow, Corvus brachyrhynchos, is remarkable--twice as big as a Blue Jay and two-thirds the size of the Common Raven.  Crows are beautiful, all-black, intelligent birds that are frequently studied by researchers as my post from yesterday points out.  They are social creatures that live in roosts of anywhere from a few hundred to two million. Two million! Crows are known to make and use tools.  The Cornell Lab of Ornithology site gives the example of “a captive crow using a cup to carry water over to a bowl of dry mash; shaping a piece of wood and then sticking it into a hold in a fence post in search of food; and breaking off pieces of pine cone to drop on tree climbers near a nest.” They are also wonderful family birds.  As Leslie Day writes, “Crows mate for life.” They share responsibilities.  Both parents build the nest.  The females incubate the eggs, the males bring food, and since they do not breed until they are two to four years old, the young also help their parents raise the nestlings.  Seems like a good system.  Like so many things about them, American Crow eggs are beautiful.  They are about 1 ¾” long and a little more than 1” wide; they vary in color from pale bluish-green to olive-green with blotches of brown and gray toward the large end.  I drew the pale bluish-green color shown here for the Field Guide because I thought it was not only gorgeous but also surprising.  How many people seeing a twiggy nest lined with pine needles and animal hair in the crotch of an evergreen tree would know that the pale bluish eggs inside belong to the American Crow? 

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