The status and ecology of the last wild population of Madagascar Pochard Aythya innotata

Abstract

SummaryOne of the rarest birds in the world, the Madagascar Pochard Aythya innotata was thought to be extinct until a small population was found in 2006. Little is known about this diving duck as it had not been studied prior to its decline and disappearance. Its rediscovery provided the opportunity to study this species in the wild for the first time and to assess the viability of this last remaining population. The population is small, fluctuating around 25 individuals, and mainly utilises two small volcanic lakes in the far north of Madagascar. Nesting occurs on only one of these lakes, Matsaborimena. Nest success (76% in 2007–2008) and hatching success (89% in 2007–2008) are both comparable to other Aythya species, but fledging success (4% in 2011–2012) is extremely low. Duckling mortality rates peak between 14 and 21 days old. We propose that starvation is the major cause of duckling mortality. Examination of faecal samples and stable isotope analysis of feathers and potential food items provide evidence that adult pochards are insectivorous, favouring caddis fly larvae. Macroinvertebrate density in the benthos of Matsaborimena is low. Adults spend 38% of daylight hours foraging, mainly in the shallowest water. However Matsaborimena is steep-sided and has no areas shallow enough for diving ducklings to feed. We conclude that these lakes are not good breeding habitat for this species. The Madagascar Pochard’s persistence here and not at other sites is probably due to a lack of the human-induced habitat degradation that has impacted many other wetlands in Madagascar.

Profound and pervasive degradation of Madagascar’s freshwater wetlands and links with biodiversity

“…Other taxa were recorded too infrequently to analyse links with human disturbance, although there is some reason to think they may also be affected by disturbance. The historic decline of the Critically Endangered Madagascar pochard ( Aythya innotata ) [ 31 ] appears unsurprising in the context of our results–the one site at which it occurs was the least disturbed site in our survey. However, despite the clarity of our results, we cannot be sure that those aspects of biodiversity that we were able to measure in our brief surveys will act as good indicators for other taxa of concern, notably fish, and this is an area that urgently requires investigating.…”

Taxonomic and Geographic Bias in Conservation Biology Research: A Systematic Review of Wildfowl Demography Studies

“…These include Critically Endangered species from low-income African and Asian countries/regions, which have declined rapidly due to habitat loss and direct exploitation (e.g. Baer’s Pochard; Madagascar Pochard Aythya innotata ) [ 47 ]. Two Asian species, Crested Shelduck and Pink-headed Duck, may already be extinct in the wild but are still being sought [ 35 ].…”

Educational Approaches to Encourage Pro-Environmental Behaviors in Madagascar

“…The native endemic flora and fauna of Lake Alaotra and its marshes are also threatened due to these human-made pressures. Considering waterfowl as an example, the Alaotra grebe (Tachybaptus rufolavatus) has already been declared extinct, the Madagascar pochard (Aythya innotata) is in steep decline and lost from Lake Alaotra, and Meller's Duck (Annas melleri) is listed as threatened [97]. Additionally, the critically endangered Alaotra gentle lemur (Hapalemur alaotrensis) or Bandro (the vernacular name) is one of the most threatened primates in the world.…”