Mexican Chickadee

Poecile sclateri

(c) Hans Spiecker
  • PARIDAE
  • Passeriformes
  • Carbonero mexicano
  • Mésange grise
Introduction

This southernmost of U.S. chickadees barely crosses our borders. Fortunate birders may encounter Mexican Chickadees foraging among Douglas firs at high elevations in Arizona's Chiricahua Mountains. These birds exhibit interesting differences in vocalizations and behavior from other North American chickadees. In the non-breeding season, they often flock with other bark and foliage gleaners such as titmice, nuthatches, kinglets, warblers, and vireos.

Appearance Description
Mexican Chickadees are five inches long with an 8.25-inch wingspan, and weigh .39 ounces (11 grams). From the base of the eyes upward, the top of the head, nape, and entire bib area (chin, throat, and upper chest) are a uniform deep black; the sides of head and neck between the two black areas are white; the entire top side, including the back, rump, and upper tail, are a deep olive gray or mouse gray; the flanks and under parts are a paler olive gray. The bill is tiny and black, the eyes are dark brown in adults, and the legs and feet are a dusky bluish.
Range Map
Courtesy Kenn Kaufman
Range Distribution
In the U.S., the Mexican Chickadee is restricted to the higher elevations of two mountain ranges—the Chiricahuas in Arizona, and the Animas in New Mexico. However, the species is common and broadly distributed in the mountain forests over much of Mexico.
Habitat
This bird prefers coniferous mountain forests, except in the southern part of its range in Mexico where it also occurs in oak-pine forests. In Arizona's Chiricahua Mountains, Mexican Chickadees are found in ponderosa pine (Pinus ponderosa) forests and in spruce-Douglas fir forests; winter habitat here includes pine-oak, Arizona cypress (Cupressus arizonica), sycamore (Platanus wrightii), and alligator juniper. In Mexico, these chickadees are less restricted to coniferous forests than in the U.S. In northwestern Mexico (southern Durango), they are found mainly in oak-pine woodlands. In central Mexico's Valley of Mexico, they occupy a wider range of habitats, including dry oak woodlands, humid fir forests, and pine-alder forests.
Feeding
The insectivorous Mexican Chickadee's major food items include small caterpillars, beetles, and other insects. These birds usually capture prey by foraging through foliage. Techniques commonly used are gleaning, and hanging upside down from leaves, twigs, and open pine cones. Bark, pine cones, lichens, and galls are searched as well. The chickadee may also grab an acorn or gall and hammer on it with its bill until it is broken and the insect larvae within can be removed. Unlike other chickadees, the Mexican Chickadee does not store food.
Reproduction
In the Chiricahua Mountains, Mexican Chickadee nests have been found up to 40 feet high—on the undersides of ponderosa pine limbs, in the forks of oak trees, or in natural cavities. Mexican Chickadees also nest in human-made boxes placed up to five meters high, with sawdust and wood shavings lining the floor. The male stays close to the female during nest building, while the female excavates the nest cup and gathers nest material. Natural nests may be lined with mammal hairs, soft catkins, bark fibers, and moss. Inside nest boxes, dry fibrous material may be topped with moss and fur. The nest cavity may be filled with material to a depth of 13 centimeters.

Females generally lay a clutch of five to nine dull white eggs marked at the larger end with small, pale reddish brown spots. Smaller clutches and smaller eggs may be laid by younger birds. Only females incubate the eggs and brood the young. Upon leaving the nest, females may cover the chicks with nesting material. Upon returning, the female often applies crushed beetles to the outside of the nest cavity in a sweeping motion; these chemicals may repel predators. Males are known to feed females near the nest during incubation, and to co-feed the young after hatching. Males bring beakfuls of tiny arthropods to nestlings, or one large caterpillar per visit. They may bring food about every 20 minutes, sometimes more frequently in early morning.
Migration
Mexican Chickadees are primarily permanent residents. In Arizona's Chiricahua Mountains, some individuals move down into lower canyons in the winter; others remain at higher elevations. In Mexico, there are local movements from higher to lower elevations in winter, but differences in these movements may be due to differences in vegetation. Since winters are milder there than in more northern areas, local movements may be less pronounced.
  • 2,000,000
  • unknown
Population Status Trends
Although Mexican Chickadee populations seem stable within their limited U.S. range, the small number of breeding birds here leads to concern about its long-term persistence. The species is also vulnerable to habitat loss within Mexico.
Conservation Issues
Given the limited distribution of the Mexican Chickadee's small, isolated populations within the U.S., habitat preservation takes on particular importance. As with other vertebrates of the U.S. mountain "islands," the non-contiguous nature of suitable habitat and these birds' limited dispersal reduce genetic variability. Although more information is needed on U.S. population densities, the long-term future of U.S. populations of Mexican Chickadee and other Sierra Madrean animals seems precarious. Genetic analysis would help better assess the degree of inbreeding presently occurring. 

Mexican Chickadees use a broader range of forest types in Mexico than in the U.S.; hence the species may be less threatened there. Oak woodlands have been used for centuries as a source of wood and fuel in central Mexico, so their present distribution is restricted. In northwestern Mexico, however, which is traditionally less populated, oak and oak-pine woodlands are widely distributed and modified mainly by livestock grazing. Logging is prevalent in northwestern Mexico, where the states of Chihuahua and Durango account for most of the timber production in the country. Although pine forests are heavily logged, they are extensive. In central Mexico, chickadees are most abundant in fir forests. These fir forests are especially threatened by logging because of their patchy distribution—mostly in the volcanic belt of central Mexico. Conserving this type of forest preserves Mexican Chickadee habitat and is necessary to avoid loss of species.
What You Can Do
Consider reducing the number of catalogs and junk mail you receive and purchasing recycled paper products where possible. Reduced logging for paper helps to save trees where chickadees live and nest.
More Information
Audubon's Important Bird Area program is a vital tool for the conservation of Mexican Chickadees and other species. To learn more about the Important Bird Areas program, visit: www.audubon.org/bird/iba/.
Natural History References
Ficken, M. and J. Nocedal. 1992. Mexican Chickadee. In The Birds of North America, No. 8 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC.: The American Ornithologists' Union.

Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York. 1996.

Sibley, David A. The Sibley Guide to Birds. Alfred A. Knopf, New York. 2000.
Conservation Status References
Ficken, M. and J. Nocedal. 1992. Mexican Chickadee. In The Birds of North America, No. 8 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC.: The American Ornithologists' Union.

Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York. 1996.

Sibley, David A. The Sibley Guide to Birds. Alfred A. Knopf, New York. 2000.