Olives and their effect on the plumage of Spotted Turtle-Doves Streptopelia chinensis and Crested Pigeons Ocyphaps lophotes in suburban Adelaide

During winter Crested Pigeons Ocyphaps lophotes and Spotted Turtle-Doves Streptopelia chinensis often develop dark-brownish plumage in suburban Adelaide. Up to 80 per cent of pigeons and doves censused in the Gilberton area developed darker plumage This darkening coincided with the presence of European olives Olea europea in the birds‚ diets. We argue that these pigeons and doves splash olive oil and an associated dark-purplish pigment onto their feathers while tearing chunks of mesocarp from fallen olives. Captive birds fed on a diet that included ripe olives developed the dark plumage while birds fed only on grain did not. Birds fed mainly on olives also lost weight.

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