Ornithological Notes

Abstract

TO the February number of British Birds the Rev. F. C. R. Jourdain and Mr. Clifford Borrer contribute an article on erythrism in the eggs of British species, that is to say, eggs in which the normal type of colouring has been replaced by one in which the markings are of various shades of red or reddish-brown ; in other words, those in which the pigment consists solely of oörhodein ; but the range of colour-variation in the species includes eggs coloured with bile-pigment (biliverdin), either alone or with other pigment, to form the various greens and blues. For this reason the eggs of the Accipitres, which, although really erythristic, seldom show traces of other colouring matter, are excluded. As might have been expected, the erythristic variation generally extends to the entire clutch. Whether individual birds which lay erythristic eggs in one season, do so always, is a point to which no reference is made.