NT
Northern Screamer Chauna chavaria



Justification

Justification of Red List Category
This species qualifies as Near Threatened because it has a moderately small and declining population; it almost meets the requirements for listing as threatened under criterion C2a(i).

Population justification
The population estimate of 2,500-9,999 individuals is derived from P. G. W. Salaman in litt. (1999). This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals. The population in Venezuela has been recently estimated at approximately <1,000 individuals (C. J. Sharpe in litt. 2015).

Trend justification
A slow and on-going population decline is suspected owing to habitat loss and possibly egg-collecting and hunting.

Distribution and population

This species occurs in north-west Venezuela (around Lago Maracaibo in Zuila, Mérida and Trujillo) (Meyer de Schauensee and Phelps 1978) and north Colombia (from the lower Atrato valley east to the Ciénaga Grande de Santa Marta and the Cesar valley, and south in the middle Magdalena valley to south Bolívar) (Hilty and Brown 1986). The upper Cauca valley holds a tiny, isolated and apparently declining population (Naranjo 1986). Numbers had been estimated at c.2,000 individuals in Venezuela but are now thought to be <1,000, possibly as small as the low hundreds (C. J. Sharpe in litt. 2015). The total population has been estimated at 3,000-5,000 individuals (Callaghan in prep.). However, this may under-estimate the Colombian population, with c.5,000 or more birds perhaps a more accurate guess (Rodríguez and Rojas-Suárez 1995). The global population is estimated to be 2,500-9,999 individuals.

Ecology

This species is restricted to lowland marshes, swamps, lagoons, the banks of slow-flowing rivers and seasonally flooded alluvial plains, often in areas surrounded by forest (del Hoyo et al. 1992). It is exclusively vegetarian, grazing the green parts of succulent aquatic plants (del Hoyo et al. 1992), although digging for unknown food items is regular (Naranjo 1986). The nest is a large mass of marsh vegetation built up from the water, and 2-7 eggs are laid mostly in October to November, but breeding continues throughout the year (del Hoyo et al. 1992). Home ranges of pairs and family groups in Valle del Cauca averaged 0.11 km2 on the edge of a lagoon (Naranjo 1986).

Threats

Loss of habitat owing to drainage of wetlands for cattle and agriculture is probably resulting in slow population declines (Callaghan in prep., Naranjo 1986), but is unlikely to affect seasonally flooded and deeper wetlands in the near future (P. G. W. Salaman in litt. 1999). Collection of eggs (A. Cuervo in litt. 1999), capture as pets (P. G. W. Salaman in litt. 1999, T. Donegan in litt. 2012, C. Ruiz in litt. 2012) and possibly illegal hunting in some areas, are unquantified threats (Callaghan in prep., C. Ruiz in litt. 2012). Construction of a pipeline and road through the wetlands of the Ciénaga Grande de Santa Marta and Isla de Salamanca in the mid-1970s obstructed tidal flow and caused extensive mangrove die-back, continuing until at least 1992 (Wege and Long 1995). In the same area, there is domestic and industrial pollution and sewage, urbanisation and mangrove cutting. Hydroelectric schemes alter hydrological regimes which may impact on the species's habitat in some places.

Conservation actions

Conservation and Research Actions Underway
It occurs in Salamanca National Park and Ciénaga Grande de Santa Marta Flora and Fauna Sanctuary, Magdalena, Colombia, but these areas have now lost sizeable areas of habitat (Callaghan in prep., Wege and Long 1995). Other less damaged protected areas include Los Katios National Park, Chocó, Colombia (P. G. W. Salaman in litt. 1999) and Ciénagas de Juan Manuel, Aguas Blancas y Aguas Negras Faunal Reserve, Zulia, Venezuela (Rodríguez and Rojas-Suárez 1995, C. J. Sharpe, J. P. Rodríguez and F. Rojas-Suárez in litt. 1999)

Conservation and Research Actions Proposed
Census and monitor populations to assess the global population and demographic trends and to refine the distribution and locate strongholds (Rodríguez and Rojas-Suárez 1995, P. G. W. Salaman in litt. 1999, C. J. Sharpe, J. P. Rodríguez and F. Rojas-Suárez in litt. 1999). Investigate its ecology, threats and conservation requirements (Rodríguez and Rojas-Suárez 1995, C. J. Sharpe, J. P. Rodríguez and F. Rojas-Suárez in litt. 1999). Improve the management of protected areas that are suffering encroachment and degradation. Increase the area of suitable habitat that has protected status. Control pollution in the species's habitats. Raise awareness of the species and its status in an effort to reduce persecution.

Identification

76-91 cm. Huge and heavy-bodied peculiar goose-like bird. Distinctive head pattern, with grey crown and shaggy crest. Broad white chinstrap across throat and sides of face, and black neck. Otherwise dull with grey underparts and dark glossed green upperparts. Sharp spurs on bend of wing. Very large reddish-pink legs, with unwebbed feet. Voice One of the loudest birds in the world, with powerful bugled klerr-a-ruk, cherio.

Acknowledgements

Text account compilers
Benstead, P., Capper, D., Isherwood, I., Pilgrim, J., Sharpe, C J, Stuart, T., Symes, A. & Ashpole, J

Contributors
Cuervo, A., Salaman, P., Sharpe, C J, Diaz-Jaramillo, C., Stiles, F., Cortés, O., Ruiz, C. & Donegan, T.


Recommended citation
BirdLife International (2022) Species factsheet: Chauna chavaria. Downloaded from http://www.birdlife.org on 28/06/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/06/2022.