At this time of year our gardens seem to be populated by sickly looking birds such as ragged robins, bedraggled blackbirds, shabby starlings, jaded jays, mussed magpies and tatty tits. The subject of feather moult is fraught with variation by species, birds within species, frequency, timing, duration, life-style and is full of exceptions but most go through a post-breeding moult, hence the “pulled through a hedge…