Sexing starlings Sturnus vulgaris using iris colour
We took blood samples from 100 post?fledging juvenile Starlings Sturnus vulgaris for DNA sexing in late August, and scored the traits that are commonly thought to predict sex in adults: iris colour, length and shape of the throat feathers, degree of speckling of plumage, body mass and tarsus length. Using logistic regression, the iris colour alone predicted the sex, as determined from the DNA, with 97% accuracy. By using iris colour and the length of the throat feathers together, 98% of birds were sexed accurately and greater separation of groups was achieved. These features were still reliable in the following February, when the birds had come into breeding plumage. At this stage, the colour of the base of the bill was 100% accurate in predicting sex.