Yellow and black Common Magpies Pica Pica

Two yellow and black Common Magpies Pica pica were observed in Sømna, Norway, in 2014. The normally white parts of these birds were all evenly coloured yellow, while the black parts looked normal. Carotenoids are normally responsible for yellow colours in feathers, but Magpies are not among the bird species for which carotenoids have been identified and such colouration in Magpies is not described in the literature. After feedback from the public and investigation of more than 4000 Magpie pictures on the Internet, I found only a total of 10-11 yellow and black Magpies at seven locations (China, Denmark and Norway) between 1989 and 2015. One moulted feather from the birds in Sømna, analysed under a light microscope, showed that the colour came from the environment. A chemical analysis of the feather including 64 elements, showed increased levels of iron (Fe) when compared to a normal white and black feather. It is therefore probable that bathing in rusty water gave the Magpie this rare colour.