This month’s Mesilla Valley Audubon Society Bird of the Month is the Chihuahuan Raven. Its scientific name, Corvus cryptoleucus, roughly translates to English as “crow with the hidden white.” At one time, the bird’s North American “official” common name was White-necked Raven since the base of its neck feathers are white. This is best seen on windy days. Since winds are common in the dry open desert habitat of the Chihuahuan Raven, and loose feathering is an adaptation you’d expect a black desert dwelling bird to use to stay cool, seeing this raven’s white neck might be more common than one might think.
A friend and I were birding a few years ago and — based on size — identified a Common Raven. This was unusual, as the habitat and elevation weren’t right, Common Ravens being birds of higher mountainous areas and dense forest. It was perched on a Yucca stalk about thirty meters from the road we were on west of Las Cruces. We stopped, put binoculars on it and, satisfied that it was a Common Raven, were about to drive on when the wind ruffled its feathers and revealed the hugest Chihuahuan Raven I’ve ever seen.
So size, while suggestive in distinguishing between American Crows (small), Chihuahuan Ravens (medium), and Common Ravens (large) is not a definitive ID clincher. Several other factors are more useful in that arena. Habitat is one. Chihuahuan Ravens almost never stray from their desert environment. Common Ravens may range down into croplands and desert during the winter, though, and forage with their smaller cousins. Chihuahuans are more social birds than Commons. The former, much like crows, frequently flock together; the latter, seldom do so and are almost always seen singly or, at most, in pairs. A Chihuahuan appears almost gaunt and scrawny compared to a Common. All this can be helpful in establishing identity, but a close look at bills and tails is more productive.
Both ravens have “Roman noses” of beaks. The Chihuahuan’s is shorter and blunter, though, and the upper mandible is sheathed with bristly feathers for half to two thirds of its length. Commons have less feathering on their upper bill, which is noticeably longer and more daggerlike.
These distinctions might not be easy to see in the field, though. However, there is one that is: the tail. Common Ravens have a diamond or wedge shaped tail. A Chihuahuan Raven’s tail is straight sided, but with a round fan-shaped end.
The vocalizations of both raven species are similar as well. In general, those of the Chihuahuan Raven are slightly flatter, less musical, more parched throat sounding and less interesting than its larger cousin. Think immature Common Raven just learning its repertoire.
Throughout its entire range (from southeast Colorado to southwest Kansas, western Oklahoma, western and southern Texas, New Mexico, southern and eastern Arizona and south into Mexico) the Chihuahuan Raven is a permanent resident. Usually beginning in September and October, though, they commonly abandon parts of their breeding range and congregate in large flocks centered on agricultural and urban areas (with their landfills) that promise ample food supplies for the winter. These flocks may number in to the thousands. By February and March, spring dispersal back to breeding habitat begins.
The Bird of the Month feature is brought to you by the Mesilla Valley Audubon Society, the local chapter of the National Audubon Society. To learn about MVAS and its activities, including monthly fieldtrips and beginner bird walks, visit new-mexico-birds.com/