Melanistic Silvereye and Thornbill

A couple of weeks ago I saw a strange bird, alone, at the birdbaths. At the first glimpse I thought it was a small honeyeater of some kind, similar to the White-naped Honeyeaters that are frequent visitors. When I briefly saw it the second time I noticed that although it had a black face it had a broken white eye-ring and looked like an odd Silvereye.

The third time I saw this bird it was with other Silvereyes and I got a much better look at it. I had my camera with me and managed to get a few, poor, shots that show its fascinating plumage. Most people are familiar with albinistic birds with feathers that have lost pigmentation; this Silvereye is melanistic. It has a genetic mutation that has caused the over-production of melanin (dark brown/black pigment) resulting in feathers that are black, or darker, than usual for the species. The angle of this shot makes it look as though the colouring on its face could be shadow, it isn’t. This bird’s face is black and the amount of dark feathers is quite extensive.

The photograph above shows typical Silvereye plumage, for comparison. The stark difference of the melanistic bird, and the fact that it visited the birdbaths alone, mean I managed to forgive myself for my initial thought that it was some species of honeyeater I was unfamiliar with. Melanism in birds is rarer than albinism.

Considering how rare it is to see a melanistic bird you can imagine my shock when I was watching for the melanistic Silvereye and this Brown Thornbill turned up! I’m staggered to have two melanistic birds turn up in the same week. I’m especially fond of thornbills and find this ones markings quite beautiful.

Again, I’m sharing a photograph of a more typically coloured bird (though it does have one unusually light feather on its head). You can see that Brown Thornbills have dark bases to some of their feathers but nowhere near as dark as on the melanistic bird. The thornbill in this photograph has also been bathing – the difference between them is nothing to do with wet feathers.

I contacted several people I hoped would be able to give a more accurate scientific explanation of the plumage aberration in these two birds but no one was able to help. As I write, at midnight, I have found an academic article written by three experts on aberrant bird plumage – I will write to them and let you know if I hear anything fascinating.

Having just used the word ‘fascinating’ I realise that this is one of the most fascinating posts I’ve had the pleasure to share.

Happy birding, Kim

~ Prints and gifts Lirralirra Shop
~ Facebook page Kim Wormald – lirralirra
~ Facebook group  Ethical Bird Photography