Distribution

Endemic to Mexico, although formerly occurred in the United States.

Breeding Range

As far as is known, Thick-billed Parrot is limited presently to high elevations of the Sierra Madre Occidental of northwest Mexico from northwest Chihuahua and northeast Sonora south to northwest Durango. Surveys have located small breeding populations throughout most of this range, but only in pockets of reasonably well conserved habitat.

Winter Range

Normally limited to Durango, Sinaloa, Nayarit, and Jalisco, south and east through the Transvolcanic Belt of Colima and Michoacán. Interviews suggest that the species usually leaves Chihuahua and Sonora almost completely in winter, although many sightings were reported in west Chihuahua and northeast Sonora during the winter of 1997-1998 (D.Venegas-Holguín and Noel Snyder, pers. comm.).
 

Endemic to the Americas.

Primarily temperate conifer forest – i.e., mature pine-oak, pine, fir (Abies) and Douglas fir (Pseudotsuga menziesii) forest – from roughly 1200 to 3500 m. Thick-billed Parrots occur in locations where the habitat varies from mountain tops with open pine or pine-oak woodland, to thick pine and fir stands below high cliffs, which sometimes are used for roosting (Sumichrast 1869, Marshall 1957, Monson 1965, Hubbard and Crossin 1974, Schnell et al. 1974, Woodard 1980, Lanning and Shiflett 1981, 1983). Nests have been found almost exclusively at elevations above 2000 m, and usually above 2400 m (Thayer 1906, Lanning and Shiflett 1981, 1983, Snyder et al. 1994, Cruz-Nieto 1998).

Thick-billed Parrots historically nested in mature and old growth forests at high elevations, sharing their habitat with the extinct Imperial Woodpecker (Campephilus imperialis), the disappearance of which closely is correlated in time with the almost complete lumbering of local pine forests and the apparent decrease of the population size of the Thick-bills. Other important sympatric birds are the Eared Quetzal (Euptilotis neoxenus), Spotted Owl (Strix occidentalis), and Northern Goshawk (Accipiter gentilis), all which are endangered (globally, or at least in Mexico), and whose populations, along with those of the Thick-billed Parrot, are decreasing.

No large fragments of old growth forests remain in the breeding range of the Thick-billed Parrot, and the best nesting areas all are forests that have been partially degraded, although they still contain moderate densities of mature trees. Studies from 1983 reported two primary breeding areas (Cebadillas and Madera). These sites continue to be reproductive strongholds for the species.

These sites continue to be reproductive strongholds for the species.

No historic nesting records are known for the Thick-billed Parrot north of the Mexican border, but this absence could easily have been an artifact of a lack of searching for nests during the period when the species still occurred regularly in the United States, of the species' high-elevation nesting habits, and of its unusually late breeding season (Snyder et al. 1994). The species was recorded on a nearly annual basis in the Chiricahuas Mountains of Arizona in the early 1900s, strongly suggesting that it was an established breeder in this location.

Early records of Thick-bills for southeast Arizona and southwest New Mexico were summarized by Wetmore (1931, 1935) and Phillips et al. (1964). The last credible historic sightings north of the Mexican border were a flock reported by F. Fish from the Chiricahua National Monument in southeast Arizona in 1938 (Monson and Phillips 1981), and a small flock seen by Charles Hanson in the Animas mountains of southwest New Mexico in 1964 (Woodard 1980).

Unfortunately, the Thick-billed Parrot suffered heavily from shooting in the United States and was very likely extirpated north of the border by this activity (Snyder et al. 1994). Populations also have declined markedly in Mexico, and the species has been considered Endangered by the International Council for the Bird Protection (now Birdlife International) and the U.S. Government since the late 1970s (King 1977, U.S. Fish and Wildlife Service 1977). The Thick-bill also is listed in Appendix 1 of CITES. Much of the recent decline is surely due to massive logging of the pine forest of the Sierra Madre Occidental since World War II (Phillips et al. 1964, Lanning and Shiflett 1983, Lammertink et al. 1996), but the species has also been stressed by trapping for the pet and avicultural trades (Snyder and Wallace 1987). The Thick-billed Parrot is not limited to virgin forest, and can exist in selectively logged areas as long as snags suitable for nesting are available and these areas remain free of shooting and trapping.