The Nest and Eggs of the White-Bellied Wren

Abstract

The White-bellied Wren (Nannorchilus leucoguster) is a small, plainly colored, almost exclusively Mexican wren which is far more often heard than seen. It is smaller than the House Wren (Troglodytes agdon) and is brownish gray above and grayish white below, and has a fairly distinct grayish white superciliary line. Its wings and tail are faintly barred with dark brown. Its most distinctive feature is its stubby tail, which is only a little more than an inch long. In the Gomez Farias district of southwestern Tamaulipas, where I first encountered this wren in early March of 1938 (Sutton and Burleigh, 1939:36), it lives principally in the thickets of kuipilca or wild pineapple (Bromelia pinguin) , a tough, barbed xerophyte which grows in dense, waist-high mats throughout the brushy woodlands bordering the rivers as well as on the lower foothills of the Sierra Madre Oriental. Here the bird spends much of its time close to the ground, feeding at the bases of theleaf-rosettes, keeping itself more or less hidden even while singing. Its song, a tinkling, ebullient pret-til-ly, pret-til-ly, pret-til-ly, is instantly recognizable as a wren’s because of its rhythmic quality. As the bird sings it lifts its head, but ordinarily it does not assume the head-straight-up, tail-straight-down posture which is characteristic of so many wrens. Two other bird species, the Cinnamomeous Tinamou (Crypturellus cinnumomeus) and Olive Sparrow (Arremonops rujivirgatus), inhabit the huipilla beds with it in that region. .