Sierra Madre Sparrow, Xenospiza baileyi

Sierra Madre Sparrow, Xenospiza baileyi. Photograph taken within the State of Mexico, Mexico, March 2018. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

The Sierra Madre Sparrow, Xenospiza baileyi, is a member of the Passerellidae Family of New World Sparrows, which has one hundred thirty-two members placed in thirty genera, and the sole global species of the Xenospiza Genus. They are known in Mexico as gorrión serranero.

The Sierra Madre Sparrow is small in stature with a short stout tail. The sexes are similar in appearance. Their head has a black stripe through the eye, a black moustache, a black lateral stripes on the throat and a gray supercilium and ear coverts. Their underparts are rufous and streaked with black transitioning to gray on the nape. Their underparts are whitish and heavily streaked in black. Their bill is buffy above and dusky bluish gray below, their iris is grayish brown, their legs are pink, and their feet are dark.

The Sierra Madre Sparrow is found in sub-alpine semi-open bunchgrass meadows at elevations between 2,300 m (7,500 feet) and 3,500 m (11,500 feet). They forage in agricultural fields consuming ants, caterpillars, earthworms, moths, seeds, and spiders. Their nests are subject to high predation rates by avian, mammalian and reptiles. The Sierra Madre Sparrow is poorly studied and very little about their biology and behavior patterns has been documented.

The Sierra Madre Sparrow is endemic to central and northwest Mexico being limited to the Transvolcanic Belt near Mexico City and the Sierra Madre Occidental in Durango.

The Sierra Madre Sparrow is very similar to the Song Sparrow, Melospiza melodia (larger, longer rounded tail, less rufous underparts and duller upperparts and flanks) and the Savannah Sparrow, Passerculus sandwichensis (short, notched, uniformly colored tail, yellow over the eys).

From a conservation perspective the Sierra Madre Sparrow is currently considered to be ENDANGERED with populations having declined by 50% over the last century. They have also experienced range reductions and loss of habitat due to human development. Historical populations in Durango, Jalisco and México are now extinct. They are considered Endangered under Mexican Law and considered to be a species of great risk of becoming totally extinct.