Story about the saving of the Echo parakeet : https://gogetfunding.com/mauritian-wildlife-foundation-saving-the-mauritius-echo-parakeet/
Not longer classified as being Endangered : No longer Endangered: the Echo Parakeet’s 100-year recovery plan
The population is thriving and growing every year. A second population has been set up in the mountains of the East and they are breeding. More recently birds were released to establish a third population which will eventually merge with, and expand the main population in the Black River Gorges. The population needs long-term management in the form of nest-boxes and some supplemental feeding. In the late 1980s' we only knew of 8-13 birds and only three of those were females. Today we have over 750 with a vision of 1000 birds in the next decade.
This is good to hear. Given that both the Echo Parakeet and the Mauritius Pink Pigeon had very close relatives on Reunion, is there any chance of establishing populations there as well?
I would think that before like that would even be considered we would have to make sure both taxa are doing really well on Mauritius - both of these are increasing pretty well but it would be a long time before we should try to introduce anything to Reunion (if that's even a good idea in the first place).
This idea has been around since the early 1970's and there have been several proposals to translocate, Echo Parakeets and Pink Pigeons and also Mauritius Fodies and Mauritius Kestrels. The idea is a good one that would likely work but is embroiled in politics, and it is unlikely to happen anytime soon,
How's the genetic diversity of the existing populations? Is breeding success affected by inbreeding pressure? I read a study once about the very poor genetic diversity of the Mauritius kestrel and how it adversely affects them. I hope the echos are different...
This is of course an important question for any small population, and not an easy one to answer definitively. There are few inbreeding effects that we have documented in the Echo Parakeet and there are good levels of genetic diversity within the population. Inbreeding may elevate the incidence and, or the potency of Psittacine Beak and Feather Disease although the relationship is not very clear. The Mauritius Kestrels are all very inbred and show moderately elevated rates of infertility and they lay smaller eggs than they did historically, although there is no evidence that this affects them at a population level. Pink Pigeons however show a range of inbreeding impacts with elevated rates of infertility (nearly a half of eggs are infertile) and a range of nuanced impacts of inbreeding upon disease susceptibility and mortality. We have sequenced the genome of the Pink Pigeon and are trying to understand the impacts of inbreeding and how to manage its deleterious impacts. We are also planning to conduct genomic studies on the other endangered species.
Thanks for sharing this. Very interesting how different species (from different taxa) are affected differently. The number of questions exploded in my head, but I try to limit myself. Am I right in thinking that the genetics of the last remaining specimens from which all the current specimens of these species are descended is of great significance? If the founders in the breeding programme were alerady inbred, or were themselves descended from inbred lineages, there's only so much you can do. Even if you sequence the gernome of each and every surviving specimen, and choose the best pairings possible. With the pink pigeons, are you trying to identify the loci of recessive, undesirable alleles (if there are such)? If on any given loci all that's left are recessive, undesirable alleles, you are powerless (unless you resort to genetic engineering, or even cloning museum specimens). Once you release birds into the wild, you have no control over their breeding and pairing. Is that a concern? Are the Echos also picky in chosing a mate? That complicates things further. I know the problem arose with the Spix macaws. Looking back on this post... sorry, loads of questions. But so interesting!
These points are all important and I can only give a superficial answer since this is an area beyond my knowledge. Different species are likely to respond to inbreeding in various ways depending on how much genetic load, -deleterious genes, are present. Some species come through a bottleneck with few issues, others succumb. The most frequent impacts of inbreeding are reduced fertility, increased juvenile mortality and often a difference in size or shape. It is important to maintain what genetic diversity is available and to increase the population as quickly as possible to maintain the variation across many individuals. Then hopefully natural selection can play a role in selecting for the fittest individuals, and in time hope the population generates more variation by mutation........ If your population is already inbred there is little that can be done if you do not have outbred individuals of the same species to integrate. Many inbred populations persist and we should not give up on them. Hybridising with a closely related species/sub-species has sometimes worked although is not an approach of choice. With genome studies (I am now out of my depth) they can annotate the genome using data from other more intensively studied species and start to understand when most variation has been lost and identify those animals with the most favourable combinations of characters to breed from. Many wild species are picky about mates, (promiscuity is a feature selected for in captive populations) and Echo Parakeets, Mauritius Kestrels and Pink Pigeons are no exception. In the future with genetic engineering who knows what we will be able to do and hopefully through gene transfer import diversity? This is the limits of my shaky understanding but I look forward to what can be achieved with optimism.
Carl, have any genetic studies been done on the museum material of any of the endangered species you have been working with? I know from the historical sub-fossil record for dodo and some reptiles and birds some interesting work has been done in this respect!
Work has been done on museum specimens of the Echo Parakeet, Pink Pigeon and the Mauritius Kestrel. They all show a loss of genetic variation, as expected. The kestrel work was done over twenty years ago and was one of the first studies of its kind, which was published in the journal Nature. In the next few years we hope to repeat all of this work using modern techniques, and will hopefully get a better understanding what has been lost, and what impact that is having on the populations.
Thanks for this Carl. I grew up reading about these species (and the bats), it's great to have an update. I did think about hybridisation myself, but did not want to ask so many questions. I am guessing that would be a last resort. Except perhaps in cases where you still stand a chance of diluting the genes from the other (sub)species to vey low levels (and if there is a very closely related candidate with very similar behaviour). I know it was used in one bloodline with the Przewalskis, and was considered in the Northern white rhino project. It is interesting how even some mammal species like cheetahs came through a bottleneck and survived (although not without problems). Hope the inbred populations of these birds will overcome the issues from inbreeding too, and can take their place in the ecosystem as it used to be, with natural selection lending a hand. What is the ultimate target number of specimens (breeding pairs) of these species, after which you can more or less leave them be? I know the pink pigeons are in zoos, but the other two are not. What's the reason for this? Is there a plan for zoo-bred specimens to be released?
May thanks for these interesting comments. Creating sub-specific hybrids has been attempted several times for conservation and the most famous are the Florida Puma that was crossed with animals from Texas and the Norfolk Island Boobook Owl that declined to just one female and was then crossed with the New Zealand sub-species. The Peregrine Falcon was reintroduced to the Eastern States of North America, and since the local "race" was extinct they introduced peregrines of six different sub-species. All three of these projects have had some success although there have been some recent issues with the Norfolk Island Owls and they have had to introduce extra New Zealand birds. Specific crosses can not be easily justified, unless they are very closely related. The Pink Pigeon is in many collections and have been exporting birds from Europe back into Mauritius. There were many kestrels imported in UK, including young birds and established breeding pairs, from both the captive breeding programme in Mauritius and the Peregrine Fund. British collections did poorly with them, and this convinced me that to breed these rare birds you really need dedicated facilities. Few British collections had the requisite skills and facilities to breed them. There have been a few male Echo Parakeets that were brought over to UK to see how they did in UK. They survived well in one collection and died out quickly in another.
I actually managed to catch a glimpse of a male Echo at Trinity in Jersey in 2009. It was a life-long dream to go there. More a pilgrimage than just a visit. I quickly checked zootierliste.de, and I had to see that indeed many UK collections had the kestrels. I was not aware. I see that some were also sent to Tierpark Berlin. I was in touch with them on my saiga captive management project for the Saiga Conservation Alliance, but the kestrels were gone by the time I visited (May 2017), as far as I can tell. I chatted with several people there (I speak fluent German), but the kestrels never came up. Coincidentally, my conclusion concerning the saiga after a lot of research and a few visits was also that although the species is critically endangered, and captive breeding would be desirable, the species has needs and peculiarities which most zoos will not cope with. Release is also fraught with difficulty. But back to the birds. I fully agree - for what it's worth - that specialised breeding centres in-situ or very close to the release sites are the best for several reasons.And I can fully imagine why a kestrel species is not an ideal candidate for most zoos. Very interesting to hear about planned hybridisation in other species, thanks. It would be interesting to know to what extent - if at all - hybridisation changes behavioural patterns. Is there a website dedicated to the breeding programmes on Mauritius perhaps? It would be interesting to read about developments from time to time. Durrell's projects (or what started as those) will always be of special interest to me. I am in my early 40s, but still remember reading the books a child (with a good delay, and in translation - for 20+ years now also in English). I have considered making the pilgrimage to Mauritius as well... although in the light of the epidemic, it has now become a more distant possibility. But my interest remains. Time to pop out Golden Bats and Pink Pigeons again. Also: may the most recent oil spill off Mauritius be managed properly and a disaster averted!