Eureka Nature

For posting information about natural history events in and around Eureka Springs, Arkansas.

Thursday, July 20, 2006

A Tale of two Crows

A number of folks have asked me, "what's wrong with our crows, they sound funny?" Well they sound okay for a species called a Fish Crow, which differs from the usual American Crow that most of us grew up with. So, two species of crows, two differnt calls. The usual "caww, caww" is the American, and the higher pitched rubber-ducky-like "kee-kee" is the Fish. The next question is a vaiation on, why haven't I noticed thembefore, have they always been here? Well, no. They arrived in the last twenty years or so, and have become quite common in the summer. They are migratory, while the American version is here all year. Apparently they, the Fish, started out as a primarily coastal species, specialized for water habitats, and then they started following rivers inland. Up the Mississippi, up the Arkansas and the White, first to Beaver Lake, and then to nearby lakes like Leatherwood, and even more recently, into town. Study the range maps for each of them. They have to be pretty adaptable, and something must alsobe changing in the habitat, but I don't know what that factor is. According to David Sibley, before agricultural settlement crows were adapted to mixes of woodland and openings, which have become far more common as farming has spread, but (I'm guessing) The American crow must be more cold tolerant, ie, better able to find food and shelter in winter, and critically, after ice storms or deep snow events. Possibly a warming climate has favored the fish crows in some way.

When I see them both at Lake Leatherwood, they are usually in separate flocks, or pairs, and aren't often together, tho I haven't witnessed any actual conflict. The Ameicans are slightly larger and sleeker. The Fish crows sometimes give the impression of having bad hair days. Fish Crows also spread the feathers on their necks when they call, unlike the American.


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