The Gila Woodpecker ( Melanerpes uropygialis) is a noisy, aggressive species characteristic of arid habitats in a limited part of the southwestern United States and northwestern Mexico, being most abundant on the desert mesas of southern Arizona. While we expect woodpeckers to be in the woods, some are conspicuous in the desert.
General Overview
The species is largely sedentary, with some movement to the north or to higher elevations in winter. While often closely associated with saguaros, the Gila Woodpecker also makes ready use of riparian woodlands and residential areas. The woodpecker has interesting associations with other species. It acts aggressively toward numerous species, and at the same time provides cavities for many secondary cavity-nesters.
Coverage of the species' life history is uneven: Some aspects have been studied extensively and others have been left virtually untouched. Particularly important contributions include those on general life history (Bent 1939), systematics (Selander and Giller 1963), foraging (Rosenberg et al. 1982, Martindale 1980b), physiology (Braun 1969c), vocalizations (Brenowitz Brenowitz 1978a, Brenowitz 1978b), nesting characteristics (Gilman 1915b, Soule 1964, Inouye et al. 1981, Kerpez and Smith 1990b), populations and effects of human activity (Emlen 1974, Anderson et al. 1982a, Tweit and Tweit 1986, Rosenberg et al.
Habitat and Distribution
The Gila Woodpecker is found in the southwestern United States and adjacent Mexico, usually below elevations of 3,300 feet. The species is often most common in low swales and arroyos, including riparian corridors with cottonwood, willow, and mesquite. It is fairly tolerant of human development, so long as sufficient habitat for foraging and nesting remains.
Dietary Habits
Gila Woodpeckers are omnivorous, and their diet includes a wide variety of food sources, depending on availability and season. They eat insects, small vertebrates, and berries. They peck, glean, and probe in cacti, trees, and shrubs. They forage primarily in dead vegetation, on trunk bark or large branches. Early and late in the day, they often forage higher in the vegetation and in the open, resting in the heat of the day or feeding in shaded interior vegetation.
Read also: Diet and behavior of the Woodpecker Finch
Insects and Invertebrates
Like most woodpecker species, the Gila Woodpecker consumes a variety of insects and invertebrates living in the bark of trees. They consume ants, beetles, aphids, scale insects, grasshoppers, cicadas, termites, moths, butterflies, and caterpillars. When seeking insects on tree trunks, generally probes or gleans at surface, rarely excavating for food. Foraging birds sometimes repeatedly tap when looking for food, listening for hollows with hidden prey, perhaps. They seldom drill or excavate large portions of dead trees as some woodpeckers do.
Fruits and Berries
In addition to insects, Gila Woodpeckers also consume fruits and berries. When saguaro and other cactus fruits, mistletoe, or lycium berries are available, Gila Woodpeckers consume large quantities. They also eat cactus fruits, mistletoe berries, and many other items in addition to insects.
Other Food Sources
Gila Woodpeckers are adaptable and opportunistic feeders. They are omnivorous, taking a wide range of insects, fruit, and small vertebrates, sometimes feeding on the ground for earthworms. Birds at feeding stations may eat corn, suet, and many types of fruit and nut, including pecans. They also visit hummingbird feeders and steal dog food from back porches.
Foraging Behavior and Techniques
Woodpeckers utilize a combination of sensory cues and specialized adaptations to locate and extract insects hidden within trees. Gila Woodpeckers forage on tree trunks and cacti, in outer branches of trees or shrubs, or on the ground.
Visual and Auditory Cues
Woodpeckers visually inspect bark surfaces and crevices, looking for signs of insect activity, such as small holes or irregularities in the bark. Perhaps most remarkably, woodpeckers possess the ability to hear insects within the wood. They can detect the subtle sounds of larvae feeding, scraping wood, or moving beneath the bark, allowing them to pinpoint the location of their prey.
Read also: Woodpecker Feeding Habits
Probing and Gleaning
They also use their tongues to probe into crevices and under bark, exploring potential hiding places for insects. These woodpeckers have strong head and neck muscles, and the skull is adapted to absorb the shock as the birds drive their chisel-shaped bills into the tree. The tongue is long and can be extended; its tip is bristled and sticky. Short legs, strong toes, sharp claws and stiff tail feathers keep these birds secure on the vertical surface of trees.
Specialized Adaptations
Woodpeckers possess several specialized adaptations that aid in their foraging behavior. Their strong, chisel-shaped bills are perfectly adapted for excavating wood. They can hammer into the wood with remarkable force, creating openings to access their prey. Woodpeckers possess exceptionally long tongues, often exceeding the length of their bills. These tongues are also barbed and sticky, allowing them to effectively capture and extract insects from deep within the wood crevices and tunnels. All birds have a hyoid apparatus, a set of bones that supports the tongue. The hyoid apparatus extends into two long, slender “horns” that wrap around the skull, passing beneath the jaw bone and often even encircling the eye socket, depending on the species.
Nesting Habits
Woodpeckers nest in cavities that they excavate. Gila Woodpeckers begin to establish nesting territories in midwinter, when they excavate cavities. Nest site is a cavity excavated in giant cactus or in tree (cottonwood, willow, or large mesquite), sometimes in palm trunk. Cavity usually 8-30' above ground. Both sexes take part in excavating. Cavity in giant cactus cannot be used for several months, as inner pulp of cactus must dry to solid casing around cavity; holes may be excavated one year, used the next. They defend an area about 50 yards in any direction from the nest cavity. They are among the most dominant bird species in the desert environments they inhabit. Males drive away other male Gila Woodpeckers and many other cavity-nesting bird species away from the territory. During winter, dominant males appear to take the most productive foraging territories, while females and subordinate males occupy less-productive areas.
Nest Placement and Description
Both male and female excavate the nest cavity, often in a tall saguaro cactus in a low area such as an arroyo rather than on a hill. Occasionally nests in oak, paloverde, mesquite, cottonwood, willow, or palm. The nest chamber is unlined and varies greatly in its dimensions; an average might be about 6.8 inches wide by 11 inches deep.
Reproduction
3-4, up to 6. White. Incubation is by both sexes, about 14 days. Both parents feed young. Age at which young leave nest not well known, probably about 4 weeks; accompany parents for some time thereafter. 2-3 broods per year.
Read also: The Hoxsey Diet
Ecological Role
Woodpeckers, including the Gila Woodpecker, play an important role in forest and desert ecosystems. By consuming wood-boring insects, they contribute to the health of trees and cacti. Their abandoned nest cavities also provide shelter for a variety of other bird species and animals.
Conservation Status
Across the western portion of the species' range, where an estimated 28% of all Gila Woodpeckers live, populations have been roughly stable since 1968. However, a 2016 Partners in Flight report suggested the species has suffered a 44% decline overall since 1970. Partners in Flight estimates a global breeding population of 1.5 million birds and rates the species 11 out of 20 on the Continental Concern Score, indicating a species of low concern. Nevertheless, Partners in Flight estimates the species will lose another half of its population by 2068 if current rates of decline persist. Development of desert habitat that removes mature giant saguaros has caused some declines.
Identifying Gila Woodpeckers
Gila Woodpeckers are fairly conspicuous and noisy-so finding them is mainly a job of getting into their desert habitats. Get out during the cool morning and look for them on prominent perches, especially on saguaro cactus or in cottonwood trees.
- Gila Woodpecker: Brown face, black and white barred back, white wing patches that are visible when in flight.