Aythya innotata

– Critically Endangered

Taxonomy

Kingdom:

ANIMALIA

Phylum:

CHORDATA

Class:

AVES

Order:

ANSERIFORMES

Family:

ANATIDAE

Scientific Name:

Aythya innotata

Species Authority:

(Salvadori, 1894)

Common Name/s:

English

—

MADAGASCAR POCHARD

Assessment Information

Red List Category & Criteria:

CR D ver 3.1 (2001)

Year Assessed:

2007

Assessor/s:

BirdLife International

Evaluator/s:

Bird, J. & Butchart, S. (BirdLife International Red List Authority)

Justification:

This species was rediscovered in 2006 following the last sighting in 1991. It is known from a single location where 13 birds were seen. While it may persist at other sites, the population is likely to be tiny and therefore it is classified as Critically Endangered.

History:

1988	-	Threatened (Collar and Andrew 1988)
1994	-	Critically Endangered (Collar, Crosby and Stattersfield 1994)
2000	-	Critically Endangered (BirdLife International 2000)
2004	-	Critically Endangered (BirdLife International 2004)
2006	-	Critically Endangered (Possibly Extinct) (BirdLife International 2006)

Geographic Range

Range Description:

Aythya innotata is endemic to Madagascar, where it was found historically in the Lake Alaotra basin in the northern central plateau. It is not clear why it has become increasingly rare this century. Until recently, the last certain record was at Lake Alaotra in 1960, with one unconfirmed sighting near Antananarivo in 1970. Then a single male was captured alive in August 1991. Intensive searches (including major publicity campaigns) at Alaotra during 1989-1990 and 1993-1994 failed to discover more birds. However, in 2006 the species was rediscovered when nine adults and four juveniles were observed at a volcanic lake situated 330 km north of the last known site, Lake Alaotra⁶. Reports from local people that the lake was not suitable for rice cultivation round the edge, it contained no fish and that the water was cold suggest that the species may have persisted at this new location because human disturbance has been minimal⁶. Follow up surveys in 2006 located c.20 mature individuals with up to nine ducklings observed at the same site⁸. Five birds were seen at a second lake c.3-4 km from the site but these may be part of the 20 individuals counted previously.

Countries:

Native:

Madagascar

Population

Population Trend:

Habitat and Ecology

Habitat and Ecology:

This diving duck is confined to shallow freshwater lakes and marshes that combine open water with nearby areas of dense vegetation^2,3. It probably prefers marshy areas and shallow water with significant vegetation over open-water habitats⁵. However, the site of its rediscovery is a volcanic lake with very little emergent vegetation⁸. What vegetation does grow at the lake edge may provide suitable nesting habitat. It feeds on invertebrates and aquatic plant seeds by diving frequently in shallow waters and is usually seen alone, occasionally in pairs². This requirement for shallow water to allow birds to reach the benthic flora may prevent it from using other volcanic lakes near the site of its rediscovery⁸. Clutch-size is two and nesting has been observed during March-April².

System:

Freshwater

Threats

Threats:

Lake Alaotra is under considerable and increasing pressure: the area is one of Madagascar's major rice producers, with 250 km² of the 350 km² surrounding the lake converted to rice cultivation¹. In some areas the lake has been drained and the water used for irrigation¹. Soil erosion from deforested hillsides and more intensive agricultural practices have diminished the water quality of the lake⁴. Introductions of exotic plants, mammals (Rattus) and fish, especially Tilapia, have depleted essential food supplies and likely increased nest-predation for the species⁴. The introduction of Tilapia into Alaotra probably had a devastating affect on the Pochard and other more widespread waterbirds preferring emergent vegetation⁵. Some of these species apparently died out at Alaotra but have repopulated from other parts of their ranges as water-lilies and other emergent vegetation have made a comeback along the marsh's southern edge⁵. Hunting and trapping of adults for food, and death through entanglement in monofilament gill-nets, are probably also major elements in the decline of this species³. There do not appear to be any immediate threats to the species at the site of its rediscovery, but given that it has a tiny known population, it faces significant risk from stochastic events and genetic factors, particularly inbreeding depression.

Conservation Actions

Conservation Actions:

Conservation measures underway:
Efforts are underway to conserve the last vestiges of suitable habitat at Lake Alaotra³. The Malagasy government has ratified the Ramsar Convention, and Lake Alaotra may be proposed as a Ramsar Site. Searches for the species continue, as do education and awareness programmes on the benefits of maintaining natural wetlands. However, implementation of any conservation policy for the area will be very difficult owing to Alaotra's huge economic importance for agriculture and fisheries⁴. The Peregrine Fund and the Durrell Wildlife Conservation Trust are conducting further surveys at the site of rediscovery⁷.

Conservation measures proposed:
Continue searches for extant populations. Protect areas of least-modified wetland at Lake Alaotra. Continue community surveys and wetland awareness programmes. Protect remaining habitat at the site of the species' rediscovery. Conduct further surveys to determine the existing population size.

Citation:	BirdLife International 2007. Aythya innotata. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 30 August 2008.
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