Tetrapod Zoology

The recent article about Meller’s duck Anas melleri inspired me to recycle my ver 1 article about another of Madagascar’s endemic ducks, the Madagascar pochard Aythya innotata [male shown below]. Meller’s duck is endangered, with a global population of between 3000 and 5000, but the Madagascar pochard is in an even worse position: in fact, it was regarded as extinct until 2006, when a small group of less than 20 was discovered (read on).

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In fact, just last month a joint group representing the Durrell Wildlife Conservation Trust, the Wildfowl and Wetlands Trust, The Peregrine Fund, and Ministry of L’Environement et Forêts went in quest of this population: you can read about their expedition at The Dodo Blog. Anyway, here’s the 2006 article…

So by now the cat is out of the bag, and the news isn’t news anymore anyway: the Madagascar pochard Aythya innotata, supposed extinct since 1992 (when the ‘last’ specimen died in captivity), has been rediscovered. Ducks are another of those tetrapod groups that we take for granted and regard as mundane, yet they’re actually a-maz-ing. Before getting into pochards into any detail, let’s remind ourselves how amazing ducks are.

Ducks are amazing

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At least some ducks have particularly interesting sex lives, involving over-sized sex organs, gang rape and occasional necrophilia [more duck sex shown in adjacent image; photo by Dave Martill]. Some species are bizarrely aggressive*, regularly attacking and beating other waterbirds to death. Some ducks can carry their eggs and/or their juveniles in flight, and some species practise nest parasitism. Herbivory, filter-feeding, carrion-feeding and flightlessness have all been evolved by ducks. Many duck species are amazingly mobile, and consequently have enormous global ranges (an issue which is particularly significant with regard to mallards Anas platyrhynchos and their close relatives and derivatives). Their mobility is particularly interesting for two reasons. Firstly, it means that they are particularly good at colonising remote islands, and because populations have repeatedly become sedentary after having made a colonisation, ducks have also been good at evolving island endemics. Secondly, it means that ducks excel in transporting things, such as sediment particles and small or microscopic organisms.

* Notably steamer ducks: go here for more.

Ducks – particularly herbivorous species such as pochards – have proven to be highly important transporters of aquatic plants, both as seeds stuck to their feathers or feet (a form of transport known as epizoochory), and as propagules carried in the bird’s gut (a form of transport known as endozoochory). Ostracods and small snails also get transported by ducks, in cases for distances of 30 km or so. The mobility of ducks (and other wildfowl) also has implications for the spread of viruses: recent work indicates that naturally migrating wildfowl were responsible for spreading the HPAI H5N1 virus from Russia and Kazakhstan to eastern Europe (Gilbert et al. 2006).

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Anyway, back to pochards. Sometimes called bay ducks, pochards – the tribe Aythyini – are one of four clades that together make up Anatinae, the true duck group (the other anatine clades are Malacorhynchini [pink-eared ducks], Anatini [surface-feeding ducks] and Mergini [seaducks]). Found virtually worldwide, the 17 pochard species are diving ducks with high wing loadings and several specialisations for subaqueous locomotion. Some species do a distinctive leap before diving, and some have to run across the water surface before taking off (others are more typical in being able to leap directly from the water’s surface). Pochards are mostly migratory, breed near permanent bodies of freshwater, and, except three of the scaups, all are predominantly herbivorous [Common pochard Aythya ferina shown here, from wikipedia].

The sad ‘loss’ of the Madagascar pochard

So back to the latest news from the world of pochards: the amazing rediscovery of the Madagascar pochard, also known as the Madagascar white-eye. First described from Lake Alaotra in central-eastern Madagascar in 1894, it was apparently still common during the 1930s and was even said to still be common in Soothill & Whitehead’s 1978 Wildfowl of the World. This was incorrect, however, as in fact the species hadn’t been found at the lake since 1971 (Young & Kear 2006), and the last published sighting comes from 1970. Furthermore, the 1970 sighting is controversial: it described an observation of the pochard at Lake Ambohibao (near Antananarivo), and as such is (so far as I can tell from the literature) the only sighting made away from Lake Alaotra. Incidentally, pochard bones from Reunion may or may not be anything to do with the Madagascar pochard (Mourer-Chauviré et al. 1999): if the Reunion bones are referable to this species, then it had a far wider range in the recent past than it did in the 19th and 20th centuries.

Following the pochard’s decline, thorough searches failed to reveal any trace of its continued presence. However, a publicity campaign amongst villages around Lake Alaotra in 1989 then led to the 1991 capture of a single male. He was kept in captivity, but died in 1992, and little about the biology and behaviour of the species was learnt from the individual. This is unfortunate as the Madagascar pochard is particularly poorly known, though given that its specific name means ‘unremarkable’, you might think that there isn’t much to know about it. We do know that, like other pochards, it feeds by diving, probably for the seeds of water-lilies and other plants. It may also eat some invertebrates.

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The Madagascar pochard’s decline and apparent extinction seems predominantly to have resulted from extreme habitat degradation and the introduction of both herbivorous and carnivorous fish. Severe deforestation of the local hills has resulted in silting-up of the lake, the consequence of which has been the spread of papyrus marsh, the consequence of which has been the setting alight of the marshes to stop them spreading, the consequence of which has been the inadvertent killing of nesting birds. Carp (introduced in 1926), tilapia (introduced in 1955) and black bass (introduced in 1961) are among several alien fish that now live in Lake Alaotra. These fish appear to compete with native waterbirds by eating the same plants and invertebrates, and the larger, carnivorous fish species may predate upon pochard ducklings. Nylon monofilament gill-nets, hidden by local fishermen in open water or at the bases of aquatic plants, are thought to have seriously affected diving birds, including the pochard as well as grebes (Young & Smith 1989).

Given all these problems, it is not surprising that the pochard declined to apparent extinction. The Alaotra or Delacour’s grebe Tachybaptus rufolavatus [shown above], discovered in 1929 and described in 1932, is unique to the lake and also appears to have become extinct (partly due to hybridisation with the African little grebe T. ruficollis capensis). Lake Alaotra is also home to the Alaotra lemur Hapalemur griseus alaotrensis [image below]: the only primate that spends most of its life in marshland. Confirming the presence or absence of any of these animals, particularly the pochard, is difficult however as ‘the marsh is so extensive and difficult to travel in that the duck could easily go undetected inside it’ (Young & Smith 1989, p. 23).

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As an extinct species, the Madagascar pochard would join a long and sorry list of recently extinct wildfowl, many of which were endemic to small islands. Young et al. (1996) listed an amazing 54 wildfowl that have become extinct within the last 10,000 years. Most of these are obscure and familiar only to specialists, but a handful have been widely featured in the literature and are relatively familiar. Among the latter is the Pink-headed duck Rhodonessa caryophyllacea, a highly distinctive pochard of India and Bangladesh, named in 1790 and widely regarded as having gone extinct in the 1930s or 1940s. More on this unusual species soon.

The Madagascar pochard returns

So, as announced on November 20th 2006 by The Peregrine Fund – an international conservation group that focuses on raptor-based conservation efforts – the Madagascar pochard has now been officially rediscovered. It really was hiding out, and not extinct. National Director for The Peregrine Fund’s Madagascar Project, Lily-Arison Rene de Roland, and field biologist Thé Seing Sam, observed 13 Madagascar pochards in total, four of which were juveniles (for their photos, please go here). This is great news, as if the right conservation efforts are put in place the bird might be pulled back from the brink of extinction. It also provides hope for species that are possibly extinct, but are both highly cryptic and inhabit remote and difficult areas. Err, like the Pink-headed duck? Hmm, more on that another time [photo below, showing two male Madagascar pochard, by Lily-Arison René de Roland].

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For other Tet Zoo articles on ducks and other anseriforms see…

Refs – –

Gilbert, M, Xiao, X., Domenech, J. Lubroth, J., Martin, V. & Slingenbergh, J. 2006. Anatidae migration in the Western Palearctic and spread of highly pathogenic avian influenza H5N1 virus. Emerging Infectious Diseases 12, 1650-1656.

Mourer-Chauviré, C., Bour, R., Ribes, S. & Moutou, F. 1999. The avifauna of Reunion Island (Mascarene Islands) at the time of the arrival of the first Europeans. Smithsonian Contributions to Paleobiology 89, 1-38.

Young, H. G. & Kear, J. 2006. The rise and fall of wildfowl of the western Indian Ocean and Australasia. Bulletin of the British Ornithologists’ Club 126, 25-39.

– . & Smith, J. G. 1989. The search for the Madagascar pochard Aythya innotata: survey of Lac Alaotra, Madagascar October-November, 1989. Dodo, Jersey Wildlife Preservation Trust 26, 17-34.

– ., Tonge, & Hume, J. P. 1996 Review of Holocene wildfowl extinctions. Wildfowl 47, 166-180.

Comments

  1. #1 Raymond
    August 30, 2009

    IIRC, some 2,000 plus species of birds have gone extinct in oceanic isles over the past 10,000 years, not to mention the loads of amphibians, lizards, crocodilians, mammals and invertebrates………..

  2. #2 Stefan
    August 30, 2009

    “Some ducks can carry their eggs and/or their juveniles in flight”

    That’s fascinating. Is there any more information about this?

  3. #3 Neil
    August 30, 2009

    Yes ducks ARE amazing. I spent a good while watching gadwall yesterday, along with some pochard. They are just coming out of eclipse. I find it amusing that some people regard ducks as dull coloured and boring – I usually point them towards mandarin and carolina wood ducks in full breeding plumage. mInd you a drake mallard or pochard, or even ‘dull grey’ gadwall is rather pleasing to the eye, and the camera 🙂

  4. #4 Kevin Schreck
    August 30, 2009

    Ducks: my favorite animals. Great article.

  5. #5 Jerzy
    August 30, 2009

    Great news, I hope
    for the best for the duck!

    Are you sure about Alaotra gentle lemur? The photo looks like obese crowned lemur.

    BTW – about pochard bones. It seems that bird bones are more difficult to identify that believed. Kenyon shag and recently Lord Howe island booby (both non-existing) prove that we should be more careful about naming extinct island birds from bones.

  6. #6 William Miller
    August 31, 2009

    How wonderful that it’s been rediscovered. (I just hope that it will now be conserved!)

    >>appears to have become extinct (partly due to >>hybridisation with the African little grebe T. ruficollis >>capensis).

    In “extinction by hybridization”, how is “extinct” defined? In theory, since the Alaotra grebe genes still exist in the little grebe population, could selective breeding of the most Alaotra-like ones reconcentrate those genes and re-create the Alaotra grebe?

  7. #7 Dartian
    August 31, 2009

    The Madagascar pochard looks very much like the ferruginous duck Aythya nyroca. Are they sister taxa?

    Darren:

    said to still be common in Soothill & Whitehead’s 1978 Wildfowl of the World. This was incorrect, however, as in fact the species hadn’t been found at the lake since 1971 (Young & Kear 2006), and the last published sighting comes from 1970

    Unfortunately, quite many semi-popular taxon monographs of the ‘XYZ’s of the World‘ kind are several years out of date regarding such fairly major details (in my experience anyway).

    Jerzy:

    Are you sure about Alaotra gentle lemur? The photo looks like obese crowned lemur.

    That picture seems to have been taken in Jersey Zoo, so I reckon that the identification is reliable.

  8. #8 Christopher Taylor
    August 31, 2009

    In “extinction by hybridization”, how is “extinct” defined? In theory, since the Alaotra grebe genes still exist in the little grebe population…

    To complicate matters, there’s no certainty that the Alaotra genes will persist in the hybrid population – they may be filtered out by drift or selection. I do feel that “extinction by hybridisation” is a difficult concept, and that conservation programmes often take an overly simplistic view towards it. However, I’ll admit that personally the question has me stumped.

  9. #9 Anonymous
    August 31, 2009

    Wow, I guess the fact that the pochard is a rediscovered species “supposed” to be extinct really does score high on the “HolyCrapometer”

    “Some ducks can carry their eggs and/or their juveniles in flight”

    I thought that was the sungrebe or some bird along those lines that carries its eggs and young in flight.

  10. #10 Michael O'Sullivan
    August 31, 2009

    I’m noticing a fascination with ducks

  11. #11 Sebastian Marquez
    August 31, 2009

    I met the biologist who rediscovered the Cebu Flowerpecker and Black Shama. It was pretty interesting to hear her tale and the issues with translation.

    In the local dialect, the shama and the magpie-robin have the same name, Siloy. When they were told by ornithologists that it was extinct, the people were shocked. “The Siloy is still here.” But the scientists thought they were talking about the magpie-robin not the black shama.

    I bought her a laptop and let her know I’m willing to help out anyway I can. Anyway, its a wild tangent from the topic, but I thought it was an interesting case of supposedly extinct taxa and languages issues.

  12. #12 William Miller
    August 31, 2009

    @Christopher Taylor: I didn’t necessarily mean that they would persist permanently – but this ‘extinction’ seems quite recent, and I imagine they’d persist until today, so it seems (naively) that an aggressive capture & breeding program could save those genes & maybe even reconcentrate them into something functionally identical to an Alaotra grebe.

    There’s a project (the Quagga Project) in South Africa attempting to do this with remaining Equus quagga quagga genes in E. q. burchelli

  13. #13 Darren Naish
    August 31, 2009

    Hi all, thanks for great comments. Assorted brief responses…

    — carrying of eggs and young in flight: this isn’t apocryphal (nor was I thinking of sungrebes) but well supported and reported in a large number of species. My best advice: read Johnsgard & Kear (1968). See also the previous Tet Zoo comment here.

    — yes, that is definitely an Alaotra gentle lemur (comment 6), just a very fat one. Looks nothing like a crowned lemur!

    — is Madagascar pochard close to the Ferruginous duck? (comment 7). According to Livezey (1996), the Madagascar pochard is the most basal member of a (White-eyed duck or Hardhead A. australis (Ferruginous duck + Baer’s Pochard Aythya baeri)) clade. So, they’re part of the same little group, but not each other’s closest relatives. Another clade, including Tufted duck and scaups, is the sister-group to this one.

    Livezey, B. C. 1996. A phylogenetic analysis of modern pochards (Anatidae: Aythyini). The Auk 113, 74-93.

    Finally, interesting thing about the rediscovery of the Cebu flowerpecker (comment 11): it represents one of the best examples of what Nigel Collar calls ‘Romeo error’. That is, giving up on a species when it is not definitely extinct. By the time the species is discovered to still be around, the situation has become gravely worse. Other examples are Caerulean paradise-flycatcher Eutrichomyias rowleyi and Jerdon’s courser Rhinoptilus bitorquatus.

    Oh – – Alaotra grebe: if its genes still linger, does it persist in a fashion? (comment 6 and also 8). Perhaps, but the species in the proper sense (in terms of a phenotypic expression) is almost certainly gone. Apparent hybrids were reported in the late 1980s, and unidentified grebes were observed at Lake Amparihinandriambavy in 2000, but I don’t think there have been recent reports.

  14. #14 Zach Hawkins
    September 1, 2009

    I went to Durrell conservation trust HQ in jersy last week (i was on holiday in guernsy at the time) abd was fascinated by the scale of what G.Durrell believed in and i proceded to take photo’s for my school magazine, i have read many of Geralds books and was curius about how he saved the mauritius kestral and how they are curently working on the pink pidgeon and the echo parakeet from the same island, so i woundered ‘how come they havent tried helping the takahe and the kakapo from new zealand yet?

  15. #15 Stefan
    September 1, 2009

    Thanks a lot for the information about carrying of eggs and young in flight 😀

  16. #16 angel
    July 24, 2010

    I find it amusing that some people regard ducks as dull coloured and boring??? I find ridicolous how humans never ever understood that nature isn’t a toy for restless kiddsss. ducks should be what they want, and genicide of their genus isn’t punishable, fortunately for us.
    Regards

  17. #17 Rosel
    November 9, 2010

    Saving Species (Radio 4 NH programme) had an article about the Madagascan Pochard today.
    http://www.bbc.co.uk/programmes/b00vrvdk it should be up on iPlayer soon.

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