VU
Dot-winged Crake Porzana spiloptera



Justification

Justification of Red List Category
The vocalisations of this secretive species are still unknown, and its distribution and abundance hence remain poorly understood. However, its population is believed to be small, fragmented, and undergoing a continuing decline, qualifying it as Vulnerable.

Population justification
The population is assumed to fall in the band 2,500-9,999 mature individuals based on the low numbers usually recorded at the relatively small number of known localities with recent records, where it is described as rare to fairly common. This equates to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals. Verification of this estimate is desirable.

Trend justification
It was formerly locally frequent to abundant in Buenos Aires, but is now rare to fairly common. This may be partly attributable to a paucity of observers, but there seem to have been declines (or perhaps birds are just highly mobile in optimum habitat) at the relatively well-watched sites of Punta Rasa and the río Luján (M. Pearman in litt. 1999). Based on this information, a slow decline is suspected.

Distribution and population

Porzana spiloptera occurs in Argentina (Corrientes-Chaco [Chatellenaz and Zaninovich 2009], San Juan, San Luis [Lucero 2013], Córdoba, Entre Ríos, Buenos Aires and Santa Cruz, with one collected in Santa Fe in 1906, unconfirmed historical records from Mendoza [Chebez et al. 2008], and a presumed vagrant in Chubut), Uruguay (Canelones, Colonia, Maldonado and Montevideo, but none since 1973) and Brazil (recent records from two sites in Rio Grande do Sul) (Cuello and Gerzenstein 1962, Escalante 1983, Arballo and Cravino 1999, A. B. Azpiroz in litt. 1999, J. C. Chebez in litt. 1999, S. B. Scherer per G. A. Bencke in litt. 2000). Records from La Rioja and Río Negro, Argentina, are thought to refer to L. jamaicensis (Martinez et al. 1997, Chebez et al. 2008, Pagano et al. 2011, Lucero 2013). It is relatively widespread (16 localities in Buenos Aires with recent records from eight), but all records refer to 1-2 birds. It was formerly locally frequent to abundant in Buenos Aires, but is now rare to fairly common. This may be partly attributable to a paucity of observers, but there seem to have been declines (or perhaps birds are just highly mobile in search of optimum habitat) at the relatively well-watched sites of Punta Rasa and the río Luján (M. Pearman in litt. 1999).

Ecology

It occurs in temporary and tidal marshes, swamps, wet marshy meadows, and wet to dry grassland. In Argentina, it associates with cord grass Spartina densiflora (up to 70 cm tall) in areas of permanent, brackish surface water (Martinez et al. 1997). It has been found in seasonally wet grasslands of Spartina and Juncus acutus (Martinez et al. 1997), and has been flushed from Paspalum grass.

Threats

There is land reclamation for agriculture, and high levels of grazing and burning. At Punta Rasa, a recreational development project has resulted in an increase in visitors. Mar Chiquita, Buenos Aires, has been flooded. Birds seem to disappear for up to one year after burning (Martinez et al. 1997). In the early 1990s, cattle-grazing displaced birds at río Luján (M. Pearman in litt. 1999). Crake are regularly trapped in Buenos Aires, but there is no evidence that this species is caught (M. Pearman in litt. 1999).

Conservation actions

Conservation Actions Underway
Most records are from Mar Chiquita Biosphere Reserve (Buenos Aires), Mar Chiquita Ramsar Biosphere Reserve (Córdoba), Punta Rasa Biological Station and the Otamendi Strict Nature Reserve. It occurs in Lagoa do Peixe National Park, Brazil (S. B. Scherer per G. A. Bencke in litt. 2000). It is protected under Uruguayan law.

Conservation Actions Proposed
Survey suitable habitat within its known range in Santa Fe (J. C. Chebez in litt. 1999) and Rio Grande do Sul. Record its voice to enable further surveys using tape-playback. Study the effects of cattle-grazing. Expand Otamendi Strict Nature Reserve to encompass larger tracts of habitat. Ensure the de facto protection of Mar Chiquita Biosphere Reserve, Buenos Aires.

Identification

15 cm. Tiny, dark crake. Brown upperparts striped blackish. Dark wings with whitish barring on coverts, visible in flight. Plumbeous underparts. Darker belly barred white. Dark greenish bill, grey legs washed green. Similar spp. Ash-throated Crake P. albicollis is considerably larger and without markings in the wing. Black Crake Laterallus jamaicensis is smaller and darker, with rufous on nape and back. Voice Unknown.

Acknowledgements

Text account compilers
Pilgrim, J., Pople, R., Sharpe, C J, Symes, A.

Contributors
Chebez, J., Pearman, M., Scherer, S., Azpiroz, A.


Recommended citation
BirdLife International (2017) Species factsheet: Porzana spiloptera. Downloaded from http://www.birdlife.org on 18/10/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/10/2017.