Every now and then the keen observer of garden birds will turn up something odd. For most of us this won’t be a rare species new to the British List, instead we are most likely to be visited by a common species with a plumage aberration or other anomaly. These differences can range from albino individuals, fully white with pink eyes and bare parts, to conditions that involve feather pigmentation such as melanism (darker feathers) and leucism (paler feathers). Often these individuals are very striking, they can cause identification confusion if observers are not familiar with the size, shape and behaviour of the species involved.
Conditions such as leucism can result in just a single feather or a few individual feathers becoming white. It’s thought to be related to a poor diet. These white feathers can make the individual birds stand out from the crowd. Whilst that may not always be a good thing in a world where predation is an ever-present threat it can mean that you can track an individual bird in your garden over several years. My garden feeders attracted a female House Sparrow with one or two white covert feathers in the wings over a three year period. This year an adult Starling with a single white tail feather has visited on a few occasions over the winter, it’ll be interesting to see if it returns next winter.