Rusty Sparrow, Aimophila rufescens

Rusty Sparrow, Aimophila rufescens antonensis. Photograph taken within Reserva Monte Mojino, Alamos, Sonora, May 2018. Photograph and identification courtesy of David F Smith, Alamos, Sonora.

The Rusty Sparrow, Aimophila rufescens antonensis, is one of seven subspecies of Rusty Sparrow, five of which are found in Mexico. They are a member of the Passerellidae Family of New World Sparrows, which has one hundred thirty-two members placed in thirty genera, and is one of three global species of the Aimophila Genus. They are known in Mexico as zacatonero canelo and zacatonero rojizo.

The Rusty Sparrow is sparrow-shaped with a long graduated tail and is medium sized in stature. They sexes are similar in appearance. They have a chestnut crown with black streaking and a narrow olive-gray or dull buffy median stripe. The sides of their heads are olive-gray with a white supraloral streak. Their back and scapulars are brown and broadly streaked in black. Their wings are brown, the secondaries and inner greater coverts are chestnut, and the rectrices are chestnut brown. Their lores are dark brown, a white orbital ring, a postocular dusky stripe, a sub-moustachial stripe, chin and throat and belly that are dully grayish buff. Their bill is black and grayish-blue, their iris is dark brown, their legs and toes are brown or light brown, and their tail is rufous brown.

The Rusty Sparrow is found within a variety of scrub habitats including second growth, bushy woodlands, forest edges, overgrown clearings in oak and pink-oak at elevations up to 2,700 m (8,850 feet). They are sedentary permanent residents being non-migratory. They primarily consume fruits, small insects, seeds, and spiders. The Rusty Sparrow is shy and secretive residing in inaccessible habitat making it very difficult to study and very little has been documented about their biology and behavioral patterns.

The Rusty Sparrow is most likely to be confused with the Oaxaca Sparrow, Aimophila notosticta (smaller in stature, larger gray bill) and the Rufous-crowned Sparrow, Aimophila ruficeps (smaller in stature, smaller bill, and a rufous line behind the eye).

In Mexico the Rusty Sparrow is found from Sonora and southwestern Chihuahua south to Chiapas, and in eastern Mexico from San Luis Potosí and southern Tamaulipas south to Chiapas. The antonensis subspecies is found only within the Sierra de San Antonio in northcentral Sonora.

From a conservation perspective the Rusty Sparrow is currently considered to be of Least Concern, with stable, widely-distributed populations.