Cactus Wren

The cactus wren is a species of wren that is endemic to the deserts of the southwestern United States and northern and central Mexico. It is the state bird of Arizona, and the largest wren in the United States.

## Description

Big and bold, with strong markings and a harsh rasping voice, this bird is very different from our other temperate-zone wrens. It represents a tropical group of large, sociable wrens, with eight species in Mexico and a few more farther south. Cactus Wrens are common in our desert southwest. They are usually seen in pairs or family parties, strutting on the ground or hopping in the brush, often posturing with spread wings and tails as they call to each other. Their bulky nests are conspicuous in cholla cactus and desert trees; after the breeding season, the wrens may sleep in these at night.

## Habitat

Cactus Wrens live in scrubby areas in the Chihuahuan, Sonoran, and Mojave Deserts as well as in coastal sage scrub in California and thorn-scrub areas in Tamaulipas, Mexico. They inhabit areas with cholla, saguaro, and prickly-pear cacti, catclaw acacia, mesquite, whitethorn, desert willow, yucca, palo verde, and other desert shrubs. Small patches of prickly-pear and cholla cacti mixed with short sagebrush and buckwheat are great spots for Cactus Wrens in coastal California and northwestern Baja California, Mexico.

## Diet

Cactus Wrens eat mostly spiders and insects such as beetles, ants, wasps, grasshoppers, and butterflies. They find these while hopping on the ground and turning over leaves or by searching bushes and tree bark. Cactus Wrens also eat fruit, particularly cactus fruits. They get the majority of their water from the food they eat and rarely drink free-standing water.

## Nesting

The female initiates nest building, but after she selects the spot, the male jumps in to help out. They build the nest 3–10 feet above the ground in a cholla, palo verde, acacia, mesquite, or other desert vegetation where the nest is surrounded by thorns. Male and female Cactus Wrens build large football-shaped nests with tunnel-shaped entrances. The pair amasses coarse grass and plant fibers to create a nest about 7 inches in diameter and 12 inches long, which weighs in at 6 ounces. The entrance is around 3.5 inches in diameter—large enough for the parents to squeeze in but small enough to keep most potential predators out. They line the inside of the nest with feathers. The pair builds the nest in 1–6 days, but most of the construction takes place within the first 3 hours of each morning.

## Behavior

Cactus Wrens are inquisitive wrens that make their presence well known, singing atop tall shrubs and hopping around on the ground in the open. Cactus Wrens are active all hours of the day and spend most of their time foraging in open areas, but they move into shady areas to forage when temperatures increase. Unlike most birds, they use their nests year-round, not just for breeding. After sunset they head back to their nests for the night. They are not particularly strong fliers and generally make jerky flights alternating between rapid wingbeats and short glides. Adults pair up for the breeding by first uttering a growling sound with their wings and tail spread before they gently peck each other. In extreme droughts some pairs may forgo breeding, but in normal conditions, Cactus Wrens breed every year and sometimes raise 3 broods in a season. They defend their territories year-round. When another bird enters their territory, they spread their tails, fluff up their feathers, scold, and even give chase. If they discover a predator such as a snake near their nest they will scold and mob the predator. Snakes, domestic cats, hawks, and Greater Roadrunners prey on adults, eggs, and nestlings.

## Conservation

Cactus Wren populations declined by about 1.6% per year between 1966 and 2015, resulting in a cumulative decline of 55% over that period, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 7 million, with 43% in the U.S. and 57% in Mexico. The species rates a 12 out of 20 on the Continental Concern Score, and is a U.S.-Canada Stewardship species. Cactus Wren is not on the 2016 State of North America's Birds' Watch List. Urban and agricultural expansion threaten Cactus Wren habitat especially when cacti and desert shrubs are lost altogether.