Interestingly, Southeast Arizona is the dividing line between the two chickadee species found here, and they don’t seem to mix. The Mexican Chickadee is another species from the Occidental whose range spills out into the Sky Island region. It can be found in small numbers in the US only in the Chiricahua and Animas Mountains (New Mexico), restricted to the high elevation pine and fir forest. The Mountain Chickadee, a species from the mountain west up into Canada, also occurs in Southeast Arizona but not in conjunction with the Mexican. Both species seem to be at the extremes of their ranges here and currently do not share habitat. Telling the two apart is easy—the Mexican Chickadee lacks the big white eyebrow of the Mountain. Somewhat surprising, the Huachuca Mountains and Santa Rita Mountains have no chickadee species!
Although very understudied, the Mexican Chickadee is known to be different from other North American chickadees in behavior and vocalizations—it doesn’t store food for the winter and its calls and songs are unique. Straying a bit from the typical chicka-dee-dee-dee call (the number of dees a determiner of predator threat level), Mexican Chickadees give a chick-a-dee repeated three or four times and also have buzzy trills and frantic warbles reminiscent of wren song. Responding to predators, adults are known to rub the nest cavity entrance with the defensive chemicals of crushed beetles.
Image by Bettina Arrigoni
