About Rallus tenuirostris Ridgway, 1874
The Aztec rail (Rallus tenuirostris Ridgway, 1874) measures 33 to 42 cm (13 to 17 inches) in length. Males weigh 271 to 331 g (9.6 to 12 oz) while females weigh 220 to 268 g (7.8 to 9.5 oz). Both sexes have identical plumage. The species occurs in two morphs: dark and light. The dark morph has rich brown upperparts with blackish markings on the back, a pale pinkish cheek stripe, white chin and throat, rufous underparts, dull brown and white to pinkish cinnamon barring on the flanks, and white undertail coverts. The light morph has a pale white center to its underparts with a pinkish cinnamon wash. Juveniles have duller, darker upperparts and paler underparts than adult Aztec rails. The Aztec rail is found almost exclusively in central Mexico, within a region roughly bounded by the states of Nayarit, San Luis Potosí, Veracruz, and Guerrero. Between 2013 and 2017, however, many observations of the species were recorded in Chihuahua, most of them in the San Pedro River valley. The Aztec rail lives in both seasonal and permanent highland freshwater marshes, and occurs at elevations ranging from 800 m (2,600 ft) up to at least 2,500 m (8,200 ft).
