Aigas Field Centre
Aigas Field Centre

The dolphin, the dipper, and the ‘dunno’

3 July, 2018. Posted by Aigas Field Centre

Last month our Walking and Wildlife group had excellent views of bottlenose dolphins (Tursiops truncatus) surfacing and later an adult dipper (Cinclus cinclus) which was teaching its fledgling to swim along a stream.

Towards the end of the day, a member of the group spotted this unusual looking bird which both surprised and confused our rangers.

After some investigation, we confirm this is a black bird (Turdus merula) with a plumage abnormality.  In addition to various pigment abnormalities, plumage abnormalities can include issues with feather growth or loss. A common misconception is that pigment abnormality is albinism or leucism, however the bird is capable of producing dark feathers therefore cannot be classified as a true albino. This could be detrimental to the individual’s survival as it is more obvious to predators and it may affect communication with individuals of the same species. Plumage abnormalities are not exclusive to black birds. It is sometimes unclear as to what causes this condition, but research proposes it can derive from genetics, diet, environmental conditions, and progressive greying.

For more information, please refer to the BTO Abnormal Plumage Survey.

Words and picture by Emma Archer

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