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Tachybaptus pelzelnii 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Podicipediformes Podicipedidae

Scientific Name: Tachybaptus pelzelnii
Species Authority: (Hartlaub, 1861)
Common Name(s):
English Madagascar Grebe, Madagascar Dabchick, Madagascar Little Grebe
French Grèbe malgache
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification information: 25 cm. Small grebe with distinctive facial pattern. In breeding plumage, blackish cap and line down neck, reddish rear ear-coverts and sides of neck, pale grey cheeks, throat and foreneck, and narrow whitish line under eye between cap and ear-coverts. Reddish eye, black bill with slight whitish tip. Pale brown underparts, dark brown-grey back. Similar spp. From other grebes by greyish cheeks and front of neck, lack of gape-wattles, and white line between cap and ear-coverts. Also, from Alaotra Grebe T. rufolavatus by red eye. Hints Often on small lakes and forested wetlands, where it is easily missed, but also on larger water bodies, including rivers, where it may be found among fringing vegetation.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A3ce; C2a(ii) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Hawkins, F., Langrand, O., Rabenandrasana, M. & Young, G.
Facilitator/Compiler(s): Calvert, R., Ekstrom, J., Evans, S.W., Khwaja, N., Shutes, S., Starkey, M., Symes, A., Taylor, P.B., Westrip, J.
Justification:
This species qualifies as Vulnerable because it has a small population which is suspected to be in decline. It has been eliminated from some sites by a combination of predation by introduced fish and entanglement in monofilament gill-nets, and is suffering habitat loss to rice cultivation, and the rate of decline is likely to accelerate in the next 16 years (three generations). It has been suggested that the population size is now very small, and should this suspicion be confirmed the species may warrant uplisting in the future.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Tachybaptus pelzelnii is still widespread and reasonably common in western and central Madagascar, with pairs or individuals on many small lakes. Surveys in the late 1990s recorded the species at 25 Important Bird Areas distributed throughout Madagascar (ZICOMA 1999), but it is suspected to be undergoing rapid declines. On Lake Alaotra the number of Tachybaptus (including a small proportion of T. rufolavatus) declined from several hundred in 1985 to 10-20 in 1993, to none in 1999 (ZICOMA 1999), but 100-200 survive in the forested lakes of the northwest plateau where Aythya innotata survives (H. G. Young in litt. 2012). The current total population may number as few as 1,500-2,500 individuals (M. Rabenandrasana in litt. 2007), although clarification is required. The present decline in the population is expected to accelerate over the next 10 years as increasing wetland conversion and overfishing continues to restrict the species to small lakes that are inaccessible and unsuitable for human use (O. Langrand in litt. 2007, M. Rabenandrasana in litt. 2007, H .G. Young in litt. 2007).

Countries occurrence:
Native:
Madagascar
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:689000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:11-100Continuing decline in number of locations:Yes
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):2000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population estimate of at least 5,000 individuals, roughly equivalent to 3,300 mature individuals, is based on recent records and results of surveys since Collar and Stuart (1985). Although it has been suggested that the population is now lower than this (M. Rabenandrasana in litt. 2007), further surveys are required to confirm this suspicion.

Trend Justification:  The species is suspected to be in decline owing to habitat loss, introduced species and bycatch. This decline is expected to accelerate over the next 16 years (three generations) as wetlands are increasingly targeted for cultivation and the species becomes more restricted to small wetlands that are unused by humans (O. Langrand in litt. 2007, M. Rabenandrasana in litt. 2007, H. G. Young in litt. 2007).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:3300Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:1Continuing decline in subpopulations:No
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:Yes
No. of individuals in largest subpopulation:100

Habitat and Ecology [top]

Habitat and Ecology:Behaviour This species is sedentary but will disperse in search of suitable habitat (del Hoyo et al. 1992). Breeding has been observed during the months of August to March (Langrand 1995). Breeding pairs are territorial but sometimes nest close to one another, and groups of 150 individuals have been recorded (del Hoyo et al. 1992, Fjeldså 2004). Habitat It was thought to prefer shallow, freshwater lakes and pools, with a dense covering of lily-pads Nymphaea (Langrand 1995, del Hoyo et al. 1992, Fjeldså 2004), but has also been found in several much deeper lakes (H. G. Young in litt. 2012). It occasionally occurs in brackish waters and slow-flowing rivers (del Hoyo et al. 1992, Langrand 1995, Fjeldså 2004). It appears to be capable of breeding in the above-mentioned habitats, including small temporary lakes (ZICOMA 1999), where a suitable covering of vegetation exists. Diet It probably feeds mainly on insects, but is also known to take small fish and crustaceans (Langrand 1995, Fjeldså 2004). Breeding site The nest is a floating structure of aquatic plants, anchored to offshore vegetation, particularly waterliles (Fjeldså 2004). Clutch-size is 3-4 (Fjeldså 2004), with breeding recorded year round, but likely to be seasonal at a given site (Safford and Hawkins 2013).

Systems:Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):5.4
Movement patterns:Not a Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): The most serious threat in the west is from reduction of habitat, especially conversion for rice cultivation and cash crops, as well as the introduction of exotic fish and intensification of fishery practices (O. Langrand in litt. 2007, H. G. Young in litt. 2007). Elsewhere, e.g. at Lake Alaotra, predation of adults by carnivorous snakehead fish Channa spp. (H. G. Young in litt. 2007) and death through entanglement in monofilament gill-nets are probably significant threats. The introduction of exotic herbivorous fish (Coptodon zillii) has considerably limited the development of aquatic vegetation and favoured the Little Grebe T. ruficollis (Langrand 1995). Hybridisation with T. ruficollis has been suggested as a serious threat (Langrand 1995), but there is no supporting evidence (ZICOMA 1999), and it should be noted that all grebe species in Madagascar are extremely threatened by fishing activities and widespread habitat conversion (H. G. Young in litt. 2007). In addition, the use of pesticides and fertilisers in agriculture is increasing and freshwater ecosystems in Madagascar are severely degraded by the proliferation of exotic aquatic plants such as Eichhornia and Salvinia spp. (O. Langrand in litt. 2007). The species is apparently considered a delicacy (H. G. Young in litt. 2012) and may therefore be subject to an unknown level of hunting pressure.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
It is recorded from six protected areas, but numbers within them are small. To assess and prioritise wetlands for protection, a monitoring procedure has been proposed using birds, particularly T. pelzelnii, as indicators (Langrand and Goodman 1995). The Malagasy government has recently ratified the Ramsar Convention, and this may herald improved conservation measures for wetlands.

Conservation Actions Proposed
Initiate a monitoring programme (O'Donnell and Fjeldså 1997, ZICOMA 1999). Conduct studies to evaluate the causes of its decline, especially in relation to changes in wetlands caused by exotic plants and animals (ZICOMA 1999). Evaluate the possibility of hybridisation (ZICOMA 1999). Increase the number of occupied sites that have protected status. Work with fishermen to develop bycatch reduction measures. Employ measures to control exotic aquatic plants (such has Eichhornia and Salvinia spp.). Target awareness campaigns at farmers in an effort to reduce the use of pesticides and fertilisers. If necessary, control populations of exotic fish species.


Citation: BirdLife International. 2016. Tachybaptus pelzelnii. The IUCN Red List of Threatened Species 2016: e.T22696565A93571027. . Downloaded on 18 August 2017.
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