Zapata Rail

The Zapata rail usually breeds in Cladium jamaicensis sawgrass, building the nest above water-level on a raised tussock. Breeding occurs around September, and possibly also in December and January. American ornithologist James Bond found a nest containing three white eggs 60 cm (2 ft) above water level in sawgrass, but little else is known of the breeding biology. Rails are usually monogamous, and all have precocial chicks which are fed and guarded by the adults. The bird prefers to feed in sawgrass. The diet is not recorded, but most marsh rails are omnivorous, feeding on invertebrates and plant material. The rails may disperse in the rainy season, returning to permanently flooded areas in the dry months. Like other rails, this species is difficult to observe as it moves through the sawgrass, and may crouch to avoid detection, but is not usually particularly wary. When disturbed, it may run a short distance and then stop with its tail raised and the conspicuous white undertail showing. Despite its short wings, the Zapata rail may not be completely flightless. On morphological grounds it would be classed as a flightless species, since the pectoral girdle and wing are as reduced as in other species of rails that are considered to be flightless, but Bond reported that he saw one flutter about ten feet across a canal.

This rail is a Cuban endemic restricted to the northern part of the 4500 km (1740 mi) Zapata Swamp, which is also the only location for the Zapata wren, and the nominate subspecies of the Zapata sparrow. The favoured habitat of the Zapata rail is flooded vegetation, 1.5–2.0 m (60–80 in) tall, consisting of tangled, bush-covered swamp and low trees, and preferably near higher ground. Typical plants of the swamp are wax myrtle, the willow Salix longipes, the sawgrass Cladium jamaicensis, and the narrow leaf cattail. The species was once more widespread, with fossil bones found at Havana, Pinar del Río and the Isla de la Juventud. Barbour did not believe that the rail, Zapata sparrow and Zapata wren were relics in the sense that they once ranged widely over Cuba (as did, for example, the dwarf hutia and the Cuban crocodile), since the birds are so highly modified for swamp conditions. He considered that conditions similar to those found today may once have extended over the large submerged area now represented by the shallow banks, with scattered mangrove keys, which stretch towards the Isla de la Juventud and perhaps eastward along the southern Cuban coast. The birds fossilized at Isla de la Juventud are smaller than the single extant specimen, but the paucity of available material makes it impossible to establish whether the populations were genuinely different.

Island species of rails are particularly vulnerable to population loss since they frequently and rapidly evolve to become flightless or very weak fliers, and are very susceptible to introduced predators. Fifteen species have become extinct since 1600, and more than 30 are endangered. The species appears to have been easily found in the Santo Tomás area until 1931, but there were no further records until the 1970s when birds were found 65 km (40 mi) away at Laguna del Tesoro. The few records in subsequent years suggest that numbers remain low, although after no official sightings for two decades, a 1998 survey found the birds at two new locations in the Zapata Swamp. Ten rails were detected at Peralta, and seven at Hato de Jicarita. On the basis of this sample it was estimated that 70–90 rails were present in the 230 hectares (570 acres) between the two sites. As of 2016, the only sighting for several years was in November 2014. The Zapata rail is restricted to a single area, with an extent of about 1,000 km (400 mi), and its small population, estimated on the basis of recent surveys and local assessments of population densities at 250–1,000 individuals, is assessed as decreasing. In the past, grass-cutting for roof thatch was a cause of extensive loss of breeding habitat, and habitat loss through dry-season burning of the vegetation continues. Predation by introduced small Asian mongooses and rats is a problem and, more recently, introduced African sharptooth catfish (Clarias gariepinus) have been identified as major predators of rail chicks. C. cerverai was classified as endangered on the IUCN Red List until 2011, when its status was uplisted to critically endangered. This had already been suggested since, given the lack of knowledge about its calls, the rail's population may be lower than currently estimated. Two remaining sites are in protected areas: the Corral de Santo Tomás Faunal Refuge, and the Laguna del Tesoro nature tourism area. Surveys have recently been conducted throughout the species' range and proposed conservation measures include the control of dry season burning.