While photographing wildflowers on the California Coast (Dry Lagoon Beach in Prairie Creek Redwoods State Park) in May, a common raven (Corvus corax) was very interested in our activities. The raven followed Leonard and me around and closely watched our every move. At times I thought this curious bird might even start to peck at the specimens.
There are at least eight recognized subspecies of common raven worldwide. Christopher Feldman and Kevin Omland conducted mitochondrial DNA and other genetic studies on ravens from around the world. Their results indicate that there are two clades (group of organisms closely related to each other implying a common ancestor) of ravens in the United States. One clade, the “California clade”, is found only in the Southwest and is closely related to the Chihuahuan raven (C cryptoleucus) while ravens from the rest of the United States are more closely related to ravens in Europe and Asia.
These two clades may be explained by their time of arrival in the New World. Ravens evolved in the Old World and crossed the Bering Strait about two million years ago settling in the southwest. Over time the Chihuahuan raven evolved from the “California” raven. Later a second raven migration crossed the Strait and settled throughout the remainder of the United States.
Discussion continues as to whether these two clades should be separate species. However, the two groups can hybridize. Thus some believe that eventually all the ravens of the United States will merge back together.
The scientific name of the common raven attests to how long this solid black bird has been known. Corvus, the genus name, is Latin for raven. The Ancient Greek word for a crow or raven is the species designation, corax.