A facinating observation as to why the Shelley’s crimsonwing maybe so rare when compared to the three other crimsonwing finches

 

Professor Sven Cichon ,who is an honorary Rare Finch Conservation Group member based in Germany, recently sent  us this thought provoking article on : 

The beak of the finch –Impressions from two Shelley’s crimsonwing finch (Cryptospiza shelleyi) skins
at the Alexander König Museum Bonn, Germany

I visited the ornithological section of the Natural History Museum “Alexander König” in Bonn to take photographs of two skin specimens of Cryptospiza shelleyi that I knew were present in one of the most comprehensive bird skin collections world-wide. What was my motivation? Having read about this elusive bird at the RFCG homepage and blog, I eventually wanted to see the bird with my own eyes and hold it in my hands. Of course, a living bird would be much more thrilling, but knowing that this is something to fancy for the future this was a compromise for the present. Apart from these feelings of a finch enthusiast, it was scientific curiosity that urged me to see these museum specimens: I always felt uncomfortable when looking at the two known fotos of Shelley’s (the one taken by the http://www.gorilla.org-group in 2008 and the other published in 1974 in the Zaire bird book by Lippens & Wille) and at drawings in books, such as in the “Handbook of the Birds of the World” (HBW) Vol. 15, in “Birds of Africa” Vol. 7, or  in “Finches & Sparrows”(by Clement, Harris, and Davis). They all look a bit different in terms of colour and habitus. For instance, in HBW, the colours are much lighter than in Birds of Africa. Which one is more realistic? Looking at the gorilla.org-foto, which seems to be the best quality picture of a living bird that we have in our hands, it looks as if  the lighter drawing in HBW might capture it more realistically. But we all know that fotos can be misleading because a large number of possible combinations of environmental influences (in particular intensity of light) and camera settings can produce significantly different impressions of the bird. By looking at the museum skins, I therefore hoped to get a more unbiased impression of Shelley’s plumage colour and to compare it to the other crimsonwing finch species. I had previously written in the RFCG blog that when comparing the four Cryptospiza species, Shelley’s ( on the far left in both the above and below photos ) looked like a phenotypic outlier to me. If this was true and if it was reflected in the genetic relatedness to the other three species, one might also speculate about possible differences in life style and habitat requirements. ( Note the different bill sizes which may influence its dietery requirements ) This might be an interesting step towards identifying the factors responsible for Shelley’s apparent decline and the reason why C. reichenovii and C. jacksoni, who share their habitat with Shelley’s, seem to be doing fine under the same environmental influences. Sven Cichon( Read the full story on the RFCG website Latest News page www.rarefinch.co.za )

 

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