About Campylorhynchus brunneicapillus (Lafresnaye, 1835)
Campylorhynchus brunneicapillus, commonly known as the cactus wren, is the largest wren species found in the United States. Adults measure between 18 and 19 cm (7.1 and 7.5 in) in length, and weigh 33.4 to 46.9 g (1.18 to 1.65 oz), with an average weight of 38.9 g (1.37 oz). It has a thick, heavy, slightly downward-curved dull black bill that is roughly the same length as its head; its lower mandible is pale and grayish, and it has a long, rounded tail. The species has brown base coloration with white speckles. Its crown is chocolate-brown with a light red tinge, and it has a distinctive white supercilium (eyebrow stripe) that runs from the bill to the nape of the neck. The nape itself is brown with white markings, the chin is white, and the neck is mostly white with black markings. The chest is white with brown or black speckles, while the belly is generally white with scattered brown or black streaks. The rump and back range from gray to brown and are marked with white and black streaks. The lower underparts and flanks are both cinnamon-buff in color. The species has ten primary and nine secondary flight feathers, which are barred in alternating black and off-white stripes. It has twelve rectrices (tail feathers), barred in alternating brownish-black and pale gray-brown; the outer rectrices have white tips. When the bird is in flight, a white band is visible on the underside of the tail, and the tail is also patterned with alternating stripes of black, white, and brown. The legs range from brown to pink-brown. Males and females have identical plumage. Juveniles can be distinguished by their paler overall coloration, red-brown to muddy-gray eyes (adults have more red-brown to red eyes), a lack of a white nape streak, and less prominent black chest markings. Harsh summer conditions, including intense desert sun and contact with prickly vegetation, fade and damage cactus wren plumage. This feather wear can make it more difficult to identify juvenile birds. Adult cactus wrens replace worn feathers through molting, which occurs within the bird’s own territory from July to October. Not all feathers are molted in a single season. While the cactus wren resembles other species in the Campylorhynchus genus, identification is simplified because their habitats do not overlap. The visible white tail band during flight is a key distinguishing feature for the cactus wren. The spotted wren, which looks similar, is paler with fewer markings, and lives in oak woodlands, a habitat cactus wrens do not usually occupy. The cactus wren inhabits arid and semi-desert regions, and generally requires spiny cacti to use as nesting sites. Its range covers the Sonoran and Chihuahuan Deserts. This species is non-migratory, and establishes a permanent, vigorously defended territory. Territories typically measure between 1.3 ha (3.2 acres) and 1.9 ha (4.7 acres), and their size and shape change very little across seasons. Cactus wrens defend their territories from other birds by fluffing their tails and feathers and giving vocal scolding calls; they will chase persistent trespassers. The cactus wren is found exclusively in the United States and Mexico. In the United States, it occurs in California, Nevada, Utah, Arizona, New Mexico, and Texas. In California, most populations live in southern coastal areas below 600 m (2,000 ft), though some individuals have been recorded as high as 950 m (3,120 ft). The northernmost extent of the species’ range is in southern Nevada; the northernmost breeding population is recorded in Nye County, near Tonopah. In Utah, the cactus wren is found only in the extreme southwest. In Arizona, it is widespread across the southern part of the state and along the Colorado River, occurring from sea level up to 1,400 m (4,600 ft). In New Mexico, populations live in the south, ranging down along the Rio Grande and into Mexico. The cactus wren’s range is potentially expanding northward in both New Mexico and Texas. In Texas, cactus wrens occur from sea level up to 1,800 m (5,900 ft) across the Texas Panhandle, Central Texas, and as far east as Travis County. In Mexico, the species is found in Sinaloa, Sonora, Chihuahua, Coahuila, Nuevo León, Hidalgo, and throughout Baja California. On the Central Mexican plateau and in New Mexico, it can be found at elevations up to 2,000 m (6,600 ft). Populations may be expanding their range in Baja California, but the species is not found in the mountains or interior of the peninsula. Cactus wrens typically live and feed in pairs, or in small family groups from late spring through winter. Flocks of cactus wrens have been reported and are fairly common, but flocks are only seen in areas with abundant food, and never last longer than a few hours. They are ground feeders that spend much of their time on the ground. They are not strong fliers, and any flight they take is somewhat erratic, alternating between rapid wing flapping and gliding.
