Leading East African birdringer/bander confirms rarity of elusive Shelley’s Crimsonwing Finch

21 Oct

Malcolm Wilson, who is a leading birdringer (or as some people refer to him, a “birdbander”), has spent hundreds upon hundreds of hours netting birds in the Albertine Rift Valley in central Africa. He has never netted the Shelley’s crimsonwing finch and, in eight years, only seen it once in the Mgahinga Gorilla National Park in the south western part of Uganda. (This is the area where the RFCG plan to work with their Phase 3 fieldwork).

Malcolm Wilson: Leading bird ringer in East Africa

This is what Malcolm had to say when the RFCG interviewed him: “The Shelley’s crimsonwing finch is an inexplicably rare bird and we need to ask why is it so rare. It could perhaps be in a natural bottleneck or is it something more serious that we don’t know about? All these things are really important for us to find out and the work that the Rare Finch Conservation Group is doing in the region is to be admired. The finch could well be a keystone species. It could unlock a lot of facts about the ecology of the area. The fact that we don’t know what is going on gives us enough reason to justify the field research. Birds often serve as indicators as to what is happening in a particular area. “

We then asked Malcolm to explain what is meant by a bottleneck: “Birds sometimes get caught into a particular area and they breed out their success to survive in that area. They don’t sometimes have the ability to adapt to the changing environment and so it may naturally become extinct. Genetically bottle necked meaning if it is isolated they cannot have a viable population in the area they occur. “

We then asked him about the fact that Birdlife International, who classify the species as vulnerable, estimate that the species could still have between 2 000 and 10 000 left in the wild. (Yet there is still only one known photograph of the species in the world). Malcolm’s response to this was as follows: “Birdlife International sometimes use the system of habitat extrapolation to estimate quantities of birds eg If a species is seen in one particular area with a certain type of habitat then it is assumed in another area with a similar habitat the species should be present. This clearly is not the case with the Shelley’s crimsonwing because the species is virtually never seen or netted “.

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2 Responses to “Leading East African birdringer/bander confirms rarity of elusive Shelley’s Crimsonwing Finch”

  1. Sven Cichon October 21, 2010 at 21:18 #

    Hi Malcolm, (hi Eelco),

    thanks a lot for sharing your observations and thoughts about Shelley’s. The bottleneck hypothesis is an interesting one. I am trying to fully understand it; are you saying the bird might originally have inhabited a much larger habitat including environmental characteristics that it would be much better adapted to (such as more open habitat?)?

    I find two aspects quite remarkable:
    1) Shelley’s, although placed in the same genus Cryptospiza as the other three crimsonwing finch species, really is a “phenotypic outlier”. From their outer appearance, reichenowii, salvadorii and jacksoni seem to be much closer to each other than to Shelley’s. I know that it is dangerous to hypothesize about genetic relatedness from the outer appearence, but it is tempting to assume that Shelley is genetically further apart from the three others than we believe. May be it is even a separate sepcies? The best answer to this would be a molecular genetic study. One might prick a feather from one of the next netted Shelley’s and have it investigated by a molecluar genetic lab in comparison with genetic material from the other three species (which will be easy to collect).
    This would certainly cost some money, but I think the results would be very interesting.

    2) How likely is it that you are placing your nets at places that are simply not visited by the birds, although they are there? This may be a naive question from someone who has never been to a tropical rain forest.
    To me, the footings and fotos of the habitat look as if there was an impenetrable thicket and some clearings/paths where it is possible to place mist nets. I understand that many finches will visit open spaces in the rain forest to feed on grass seeds. But assume Shelley’s diet does not involve grass seeds and it just stays in the most impenetrable part of the rain forest. Hence, you would net such a bird only as a very rare exception, but it might still be there in good numbers.
    Just a thought, might be nonsense….

    And last, I just wanted to add that there is at least one other known foto of a Shelley’s. It was published in “Les Oiseaux du Zaire”, the capture of the foto says that it was fotographed in the Virunga National Park on the 10th March 1974.

    Best regards from Germany,

    Sven

    • eelcomeyjes October 28, 2010 at 08:22 #

      Hi Sven ,

      Many thanks for your recent comments . I think it is best that Malcolm or Simon perhaps try and answer your first point on bottlenecks in nature . In terms of your second point we have often discussed the netting process that we use and at times ( particularly when we were near the end of our 12 month research permit period)wondered if there perhaps was something that we were not doing correctly. Benson and his team often, using their pangas, had to cut pathways through the thick undergrowth or bamboo of the forest to set up the nets . Malcolm always advised us that we should keep the nets as close to the ground as possible which is exactly what we did . It was also suggested that we should set up a seed dish to try and attract the Shelley’s crimsonwing ,but the Ugandan Wildlife Authorities understandably forbad Benson from doing this .
      We have now made the decision that before phase 3 starts we will send Benson on a refresher netting course up in Kampala just to ensure that we are doing everything correctly and hopefully not missing a trick somewhere .

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