Aztec Rail

The Aztec rail, known scientifically as Rallus tenuirostris, is a bird of modest size, measuring between 33 to 42 centimeters in length. Males are slightly heavier than females, with weights ranging from 271 to 331 grams for males and 220 to 268 grams for females. Both sexes share a similar plumage pattern, which comes in two morphs: dark and light. The dark morph is characterized by rich brown upperparts with blackish markings, a pale pinkish cheek stripe, and a white chin and throat. The underparts are rufous with a mix of dull brown and white to pinkish cinnamon barring on the flanks, and white undertail coverts. The light morph features underparts with a pale white center and a pinkish cinnamon wash. Juveniles present a more subdued coloration compared to adults.

Identification Tips

When attempting to identify the Aztec rail, look for the distinctive cheek stripe and the barring on the flanks. The size and shape are also indicative, with the Aztec rail being similar in stature to other rails but with its own unique coloration.

Habitat

This species is found in highland freshwater marshes, both seasonal and permanent, within the central regions of Mexico. It thrives at elevations ranging from 800 meters to at least 2,500 meters above sea level.

Distribution

The Aztec rail is endemic to Mexico, with its presence largely confined to central areas, including Nayarit, San Luis Potosí, Veracruz, and Guerrero. Notably, there have been several sightings in the valley of the San Pedro River in Chihuahua between 2013 and 2017.

Behaviour

The Aztec rail is predominantly sedentary, remaining in its range throughout the year. However, some individuals may disperse to temporary wetlands during the rainy season from May to September.

Song & calls

During courtship, the Aztec rail emits a series of loud, harsh 'kik' or 'kuk' notes. Both sexes are known to produce 'chac' notes as an advertising call and a soft, rapid 'tuk' sound.

Breeding

Breeding season for the Aztec rail typically spans from May to August, but it may also include the months of April and September. Nests are dome-shaped structures made of spikerush, situated within stands of the same plant. Clutch sizes are known to consist of five eggs.

Diet and Feeding

The diet of the Aztec rail is primarily composed of crustaceans, with a particular preference for crayfish. It also consumes molluscs, terrestrial and aquatic insects, and may occasionally feed on spiders, fish, and amphibians.

Conservation status

The International Union for Conservation of Nature (IUCN) has classified the Aztec rail as Near Threatened. The species has a moderate-sized range that may be expanding, but the population, estimated at around 15,000 mature individuals, is believed to be in decline. The primary threat to the Aztec rail is habitat loss due to agricultural, industrial, and urban development.