Introduction

“Perched atop a thorny bush, he breaks the sweltering stillness of a summer afternoon with his harsh scolding notes. The noisy aggressive Cactus Wren can be heard throughout the day, even when most other desert dwellers seek seclusion in some shady niche”

(Tveten 1993: 280).

Year-round-resident of arid lowlands and montane scrub communities of the southwestern United States and northern and central Mexico, the Cactus Wren is often the most abundant member of the local desert avifauna. Although it occasionally drinks free-standing water and bathes in backyard birdbaths, this wren is well adapted to its desert environment and may be considered a true xerophile. Its diet of insects, occasional small reptiles or amphibians, seeds, juicy pulp from cactus fruit (for example, saguaro [Cereus gigantus]), and juice from wounds in cactus usually provides enough liquid to sustain individuals in their arid surroundings.

Its large size and conspicuous, noisy behavior distinguish the Cactus Wren from all other wrens with which it might occur. Its nest is a large, globular chamber with a tunnel-shaped passageway and “doorstep” or perch near the entrance. Nests are built year-round, and males often build several secondary nests—used for roosts by adults and fledglings and as breeding nests for subsequent broods—while their mates incubate eggs. In Arizona, this species may fledge as many as 3 broods a year.

In addition to the repetitive, single, staccato note frequently given by the male, the Cactus Wren’s repertoire contains at least 32 variations of the typical Adult Song. These variations are marked by distinct syllable patterns of characteristic length and rate.

The female’s song, rarely heard, is weaker and higher pitched than that of the male’s.

Although the Cactus Wren is considered a hardy species that can tolerate some human disturbance, its populations are declining with increasing urbanization and subsequent loss of native vegetation in the southwestern U.S.

To provide a comprehensive account of Cactus Wren ecology, review of more than 100 publications from various authors was essential. Interestingly, however, articles by 4 individuals (A. H. Anderson, A. Anderson, R. E. Ricklefs, and F. R. Hainsworth) contributed significantly to this account. In a 6-part journal series that culminated in a book, The Cactus Wren, boundless life-history information is provided from 30 years of study in southwestern Arizona (Anderson and Anderson 1957, 1959, 1960, 1961, 1962, 1963, 1973). Also conducting research in southern Arizona, but focusing more on nesting (for example, nestling conditioning and development of homeothermy), Ricklefs (1966, 1967, 1968) and Ricklefs and Hainsworth (1966, 1968a, 1968b, 1969) provided key physiological information on the species. Other key papers addressing ecology of Cactus Wren in arid environments of Arizona and New Mexico include: Marr 1981, Marr and Raitt 1983, Simons and Martin 1990, and Simons and Simons 1990 and 1993 .