Data Zone
Justification of Red List category
This species was rediscovered in 2006 following the last sighting in the previously known range in 1991. The current total wild population is 33-47 mature individuals, and although this represents an increase from only 25 mature individuals present in 2008 it is likely close to the maximum population that can be supported at the rediscovery site. The population is considered stable at present, but remains at great risk from stochastic threats. Conservation efforts are working to establish a self-sustaining second population alongside local communities around Lake Sofia, in tandem with work to restore wetland health, however this population is currently dependent on intensive management and cannot yet be considered in this assessment. The population remains tiny and at extremely high risk of extinction, therefore Madagascar Pochard is assessed as Critically Endangered.
Population justification
The wild population appears to be stable at up to 70 individuals (BIAZA 2022), placed in a band of 50-70 individuals. The proportion of the counted individuals that are mature is uncertain, however high chick mortality (Bamford et al. 2015) logically suggests a high proportion of adults in the population. A frequently used ratio is that two thirds of individuals are considered mature individuals, which would give a range of 33-47 mature individuals, rounded to 30-50 mature individuals. This matches the estimate derived from the data of WWT/The Peregrine Fund/Durrell Wildlife Conservation Trust with a best estimate of 45 mature individuals (P. Cranswick, A. Bamford, L.-A. Réne de Roland, H.G. Young in litt. 2019). All of this population occurs in one small area, where habitat is limited, and food density and availability is naturally low. The site is considered to perhaps be only able to support around 50 mature individuals, though numbers may fluctuate in the short term following a good breeding year (P. Cranswick, A. Bamford, L.-A. Réne de Roland, H.G. Young in litt. 2019).
Precise recent counts are of 62 present at the rediscovery site in September 2022 (S. Mahood in litt. 2022) and 64 in May 2019 (L.-A. Réne de Roland in litt. to H.G. Young 2020). Shortly after rediscovery in 2008 a total of 25 mature individuals were counted, with six pairs nesting in the 2007/08 season (L.-A. Rene de Roland in litt. 2008). No chicks fledged in 2008 or 2009 (P. Cranswick in litt. 2009, H.G. Young in litt. 2012), and only 19 adults were recorded in July 2009 (Jarrett 2010), including six females (Cranswick 2010). In 2011 there was again no successful breeding: the lake had little available suitable food (Cranswick 2012). In 2012 a total of 21 assumed mature individuals were counted (nine females and 13 males) and 20 breeding attempts were recorded (Bamford et al. 2015). Hence there has been a notable increase since 2008-2012, roughly equivalent to an increase of 127% over the past three generations, however these numbers are still so small that much of this increase may be within the range of natural population fluctuation (P. Cranswick, A. Bamford, L.-A. Réne de Roland, H.G. Young in litt. 2019). The reason for this increase is unclear, though an increase in chick survival in some years, presumably related to improved food availability appears a plausible mechanism, and the regular presence of researchers and increased awareness of the species may have halted previous low levels of hunting at the site.
No other sites are in suitable condition to support the species, so emigration from this site is highly unlikely to result in a new population elsewhere, consequently a further increase is not expected without significant conservation intervention at other sites (P. Cranswick, A. Bamford, L.-A. Réne de Roland, H.G. Young in litt. 2019).
Trend justification
The species declined dramatically in the past and became extinct in the Lake Alaotra region sometime prior to the early 1990s. This was considered the core population and was likely moderately large in the first part of the 20th century (Young and Kear 2006, Rene de Roland et al. 2007). No sightings were made until 2006, when a very small number were found at a seemingly marginal site distant from Lake Alaotra (Réne de Roland et al. 2007, Bamford et al. 2015). Numbers here increased from around 25 individuals in 2008-2012 (L.-A. Réne de Roland in litt. 2012, Bamford et al. 2015) up to near 70 individuals in 2022 (BIAZA 2022), but have been stable at around 60-65 between 2019 and 2022 (L.-A. Réne de Roland in litt. to H.G. Young 2020, S. Mahood in litt. 2022). The current trend is considered stable. The population is still extremely small and prone to stochastic events. Breeding success is very limited with no young reared in some years and detailed investigation indicated extremely high chick mortality likely due to inadequate food supplies (Bamford et al. 2015). The recent increase may be due to only one or two successful breeding years: the site is considered able to support around 50 mature individuals (P. Cranswick, A. Bamford, L.-A. Réne de Roland, H.G. Young in litt. 2019). The likelihood of dispersing young surviving away from main site is very low (H.G. Young in litt. 2012): no additional sites holding birds have been located despite searches.
This species is endemic to Madagascar (although sub-fossil remains of an Aythya duck on Reunion are attributed to A. innotata), where it was found historically in the Lake Alaotra basin in the northern central plateau. It was considered relatively common at Lake Alaotra in the 1930s, but declined dramatically through the 1940s and 1950s (Young and Kear 2006, Rene de Roland et al. 2007). Until the 1990s, the last certain record was at Lake Alaotra in 1960, with one unconfirmed sighting near Antananarivo in 1970 and several other possible records. Then a single male was captured alive in August 1991, but died in captivity a year later (Bamford et al. 2015). Intensive searches (including major publicity campaigns) at Alaotra during 1989-1990 and 1993-1994 failed to discover more birds (Bamford et al. 2015).
However, in 2006 the species was rediscovered when nine adults and four juveniles were observed at a volcanic lake situated 330 km north of L. Alaotra (S.T. Seing in litt. 2006, Rene de Roland et al. 2007). 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 minimal (S.T. Seing in litt. 2006). The population is centred on L. Matsaborimena, one of four high altitude lakes near Bemanevika, but there is clearly some movement of individuals between these lakes. Lake Andriakanala regularly holds small numbers and in March/April more individuals may be present here than at Matsaborimena, while L. Matsaborimaitso occasionally holds up to five individuals (Bamford et al. 2015). No individuals have been seen on L. Maramaratsalegy (Bamford et al. 2015). The maximum area of occupancy (AOO) for the lakes used at this site is 16 km2, however breeding has only been recorded from a small section of L. Matsaborimena, such that a minimum AOO related to breeding area would be only a single 2 km x 2 km square, 4 km2. The extent of occurrence is similarly restricted, with a minimum convex polygon around the lakes used encompassing 25 km2.
A second conservation population has been established at Lake Sofia through the release of birds reared in captivity from clutches taken from L. Matsaborimena (Gill 2009, Durrell.org 2020, H.G. Young in litt. 2020, BIAZA 2022). Releases began in December 2018 and the first breeding occurred in early 2020 (BIAZA 2022): this population is reliant on supplementary feeding in floating aviaries designed especially for the species (Bassett 2017) and currently numbers 47 mature individuals (BIAZA 2022). There are now two purpose-built captive-breeding centres in Antsohihy (H.G. Young in litt. 2020) which hold a captive population of more than 100 individuals (BIAZA 2022).
Behaviour This species is generally sedentary and usually occurs singly, or occasionally in pairs (Young 2011). It is not known to flock or to associate with any other species (Kear 2005). Nesting has been observed during the months of July to February (Bamford et al. 2015). Some pairs may make multiple nesting attempts (Bamford et al. 2015). Habitat The species was historically only known from shallow freshwater lakes and marshes that combine open water with nearby areas of dense vegetation (Langrand 1990; Morris and Hawkins 1998; H.G. Young in litt. 2003). It probably prefers marshy areas and shallow water (H.G. Young in litt. 2003). However, the site of its rediscovery is a volcanic lake with very little emergent vegetation (H.G. Young in litt. 2007). What vegetation does grow at the lake edge may provide suitable nesting habitat. The requirement for shallow water may prevent it from using other volcanic lakes similar to the site of its rediscovery (H.G. Young in litt. 2007).The nest is sited amongst lake-edge vegetation (Cyperaceae) and placed 20-40 cm above water (Bamford et al. 2015). The clutch size is 6-10 eggs (Young 2011). Diet It is believed to feed almost entirely on invertebrates with a minimal proportion of plant matter (Bamford et al. 2015).
Nationally, widescale wetland degradation – particularly from sedimentation, clearance and drainage for rice cultivation, introduced fish, and disturbance – has resulted in the decline of many wetland species (Young and Kear 2006, Bamford et al. 2017). These factors, plus some hunting of adult Madagascar Pochards for food and bycatch in static fishing nets, are likely responsible for the loss of the species across its range (Morris and Hawkins 1998) and its failure to recolonise former locations (H.G. Young in litt. 2016). Lake Alaotra, the species’ former stronghold, is under considerable pressure, located in a major rice growing region (Lammers et al. 2018). A large proportion of the lake was converted to rice agriculture during the 20th century (Edhem 1993) and sedimentation due to deforestation and more intensive agriculture reduced the water quality of the lake (Pidgeon 1996) and these drivers likely caused a significant population reduction in the species across the central plateau. However, it is most plausible that the extinction of the species from Lake Alaotra was ultimately driven by the actions of introduced species, in particular introduced fish species. Introduced plants (especially water hawthorn Eichornia crassipes) may have impacted the food supply and rats (Rattus spp.) may have caused additional chick mortality, but the impact of various predatory tilapia species (Oreochromis, Sarotherodon and Tilapia spp.) introduced after 1950 (Young and Kear 2006) appears to have been extremely high mortality of both chicks and adults and a rapid population decline to extinction by 1991, in common with Alaotra Grebe Tachybaptus rufolavatus (Hawkins et al. 2000) and the local population of White-backed Duck Thalassornis leuconotis (Young et al. 2006). Hunting and trapping of adults for food, and death through entanglement in monofilament gill-nets, are thought to have contributed to the decline of this species (Morris and Hawkins 1998), or its failure to re-colonise locations (H.G. Young in litt. 2016).
The remaining extremely small (<50 mature individuals) population, restricted to one small area, faces risk from stochastic events and potentially habitat degradation. The site is little used by people – the main reason for the Pochard’s persistence – and in reasonably good ecological condition, although the habitat is largely unsuitable for Pochards (Bamford et al. 2015). Adult survival appears normal, but fledging success is usually very low. Ducklings have trouble finding adequate food as the invertebrate density is low, the lake is relatively deep for ducklings to readily access the substrate, there is little submerged aquatic vegetation, and the site is relatively cold, so most starve before fledgling. Since its rediscovery in 2006, there has been a regular camp of researchers and conservationists close to the site and an awareness campaign in surrounding villages, which further reduce the chance of potentially damaging activities at the site or in the small catchment. The incidence of slash and burn (previously prevalent) has been reduced, though not eliminated, and firebreaks have been installed to further reduce the chance of this affecting vegetation immediately around the lake. Previously, a low level of hunting may have occurred.
Climate change may have future implications for this species, including indirect implications as a result of impacts on human populations (Segan et al. 2015), however these may be mitigated by the presence of conservationists at the site.
Conservation Actions Underway
Formal protection of the site at Bemanevika was achieved in 2015 with the creation of National Protected Area Bemanevika. Outcomes and actions are specifically identify to address threats, including the encroachment of rice growing and slash-and-burn. A permanent research camp has been established nearby by The Peregrine Fund, which, along with awareness raising among the local communities, provides protection against accidental or deliberate damage.
In 2009, 24 eggs were brought into captivity from Bemanevika by Durrell Wildlife Conservation Trust (Durrell) and the Wildfowl and Wetlands Trust (WWT) to guard against imminent extinction and create a source population for reintroduction (Jarrett 2010). A breeding centre has been built in the regional capital, Antsohihy. The birds first bred in 2011, and a captive population of around 100 birds has been established. A second facility, which houses around 20 birds, was built nearby in 2017 to allow the public to view the birds for engagement and education (H.G. Young in litt. 2020). An IUCN Species Action Plan (Woolaver et al. 2016), developed by a wide range of stakeholders, identifies conservation goals, objectives and actions. Analysis and surveys of wetlands by WWT and Durrell across the species’ presumed former range identified Lake Sofia as a release site (Cranswick et al. 2018). Following social and ecological surveys, work since 2014 with a development agency has sought to ensure appropriate management and sustainable livelihoods. The site was designated as a Ramsar site in 2017. A translocation plan to reintroduce the species to Lake Sofia (Cranswick et al. 2018) was approved by Government in 2018. Novel infrastructure was developed for the release of a diving duck including floating aviaries (Bassett 2017), and the first releases (21 birds) were in December 2018 (H.G. Young in litt. 2020). The first breeding took place in November 2019, with 8 chicks fledging in January 2020 (H.G. Young in litt. 2020, Anon. 2020). A further 35 individuals were released between September and November 2021 (H.G. Young in litt. 2022).
Lake Alaotra became a Ramsar Site in 2003. Efforts are underway to conserve the last vestiges of suitable habitat here (Morris and Hawkins 1998), but implementation of any conservation policy for the area will be very difficult owing to Alaotra's huge economic importance for agriculture and fisheries (Pidgeon 1996).
Conservation Actions Proposed
Continued close monitoring of the wild population is needed to track population trends and to detect potential declines rapidly. Ecological research of birds and habitat at Bemanevika and Lake Sofia (and elsewhere in the presumed former range), and post-release monitoring, will inform management of both sites. A habitat restoration plan for Lake Sofia is under development. Continue to monitor the wild population closely. Continue the captive-breeding programme, and supplement the population on Lake Sofia. Ecological monitoring is also required at Bemanevika.
45-56 cm. A medium-sized diving duck. Male is dark mahogany-brown all over except for white eye, white undertail-coverts, white underparts and conspicuous white wing-bar along bases of flight feathers. Bill is dull brown with paler, bluish subterminal band. Female is duller brownish, lacking white eye. Similar spp. From all waterfowl by overall dark plumage and white undertail-coverts and wing-bar extending length of the wing. In addition, from White-backed Duck Thalassornis leuconotus by uniform colouration, dark back and white eye (in male), from Red-knobbed Coot Fulica cristata by mostly dark bill, and from all other ducks by diving habit and running take-off. Hints Rather tame.
Text account compilers
Martin, R.
Contributors
Bamford, A., Cranswick, P., Hawkins, F., Hughes, B., Mahood, S., Rabenandrasana, M., Réné De Roland, L.A., Seing, S.T., Thorstrom, R., Watson, R., Westrip, J.R.S. & Young, G.
Recommended citation
BirdLife International (2024) Species factsheet: Madagascar Pochard Aythya innotata. Downloaded from
https://datazone.birdlife.org/species/factsheet/madagascar-pochard-aythya-innotata on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.