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Leucistic White-fronted Plover – or is it?

- Peter Ryan

Birders are fascinated by abnormal plumage coloration, per-haps because we rely so heavily on plumage colour to identify birds. One of the most common aberrations is a lack of pigmentation, resulting in partially or wholly white plumage. For many years such birds were called albinos – or partial albinos – until it was pointed out that albinism strictly refers to the complete absence of melanin, including in the bill, legs and eyes (which makes the eyes appear pink due to the blood vessels at the back of the retina). Albinos are extremely rare in the wild, probably because their vision is poor and they soon fall prey to predators, so we should be calling birds with at least some melanin ‘leucistic’.

But life is seldom that simple. I recently came across an unusually pale White-fronted Plover that has been on the coast south of Olifantsbos in the Cape of Good Hope sector of Table Mountain National Park for the past few years. Not having seen leucism in a plover before, I did a bit of research into leucism in shorebirds. It turns out there are very few records from plovers and sandpipers, but it is more common in avocets and oystercatchers (including the African Oystercatcher). However, I also came across a couple of interesting articles that I should have read when they first came out more than a decade ago.

The first, ‘Not every white bird is an albino: sense and nonsense about colour aberrations in birds’ by Hein van Grouw, appeared in 2006 in Dutch Birding (28: 79‒89) and was followed shortly thereafter by JeffDavis’s ‘Color Abnormalities’ in Birding