An earlier post by a beginner Indian birdwatcher attracted the attention of a veteran Malaysian birder who had also seen such odd coloured bee-eaters and was curious to know what is behind such condition. We wrote to our resident bird behaviourist in the UK for an opinion and John Vickerman kindly responded with a reply below.
“The notes which follow have nothing to do with any knowledge that I may have concerning bee-eaters (which is very little) but are wholly taken from reference to the monograph entitled “The Bee-eaters” by Dr Hilary Fry published by T. & A.D. Poyser Ltd., Calton, England in 1984. This excellent monograph presently remains the most up to date reference work on this family.
“It seems hybridisation is unknown in wild bee-eaters according to Dr Hilary Fry. However, in my opinion, that isn’t to say that it could never happen, extremely unlikely though that may be.
“Taking the observation of Suchitra V. Srinivasan first, the photograph records a juvenile bird with an interesting plumage. In Dr Fry’s book, Appendix 9 page 277, a number of aberrant plumages in, especially, juvenile bee-eaters are detailed. I quote: ‘…throat colour can sometimes be ‘wrong’. …. young Little Green Bee-eaters of all races occasionally have yellow throats instead of blue or green…’ Therefore, in the absence of conclusive evidence that mixed parentage of this particular bird is available, I believe it far more likely that it was one of these occasionally recorded aberrant plumaged, pale throated birds that was photographed.
“For someone new to birdwatching and photography, I think this is a very commendable piece of observation and even better to record it as a photograph. My congratulations! This picture is well worth keeping and could have scientific value since a lot still has to be learnt about this fascinating family of birds.
“Secondly, I think the set of pictures that Dr Amar-Singh took are more confusing because there is no reference in Dr Fry’s book of any aberration in plumages of young Blue-throated Bee-eaters. However, based on the recorded instances of occasional aberrations in juvenile bee-eater plumages in addition to Little Green Bee-eaters as described above, my money would, nevertheless, be on this juvenile bird being an aberrant juvenile Blue-throated Bee-eater.
“I apologise in advance if I am wrong, but I don’t think the Blue-tailed Bee-eater breeds in Dr Amar-Singh’s part of Malaysia, but the rusty throat of that species, theoretically at least, might come through in an unlikely union of that species with Blue-throated Bee-eater. So I have to say that it is most likely to be an aberrant plumage of a juvenile Blue-throated Bee-eater in this set of photographs.
“Again, I believe it very well worthwhile archiving this sequence of photographs for further examination by those who know more, or are conducting research, about bee-eaters. It is just these sorts of photographs that not only pose lots of questions, but can also help to confirm, or disprove, present day researchers’ deliberations.
“Dr Singh raises the issue of the rather ruffled appearance of the adult bird in a photograph. According to Dr Fry, moulting can be a rather protracted business (see page 115 of his book), and it looks to me as if this bird is undergoing this process especially as the tail streamers of this bird are a long way too short for a freshly and fully moulted adult bird.
“Once again, YC, I hope these notes may be of some interest to you and for the correspondents concerned. Plumage variations, DNA analysis and moult sequencing to name just three areas are all areas of ongoing research for PhD. students and professors around the world, and are far too technical for me! However, photographic evidence such as we see here is always very valuable to such researchers. It would be nice to think that these images can be put to further good use for research purposes.”