By Charlotte Owen
You may have noticed that the birds have been a bit quiet lately. After the cacophony of spring birdsong and the non-stop parenting of a busy breeding season, the garden can seem a little empty in late summer. There’s a distinct lack of singing, the feeders are no longer crowded and the branches are bare - where have all the birds gone?
Thankfully, they haven’t gone far. They’re just keeping a low profile while they undergo a late summer moult, with adults shedding their tired and tatty feathers to replace them with strong and glossy new ones, while this year’s fledglings moult into their adult plumage. Adults can look particularly bedraggled by the end of the breeding season but once their parenting job is done, and while the weather is still mild, there is a window of opportunity to take time out and replenish themselves. It takes about five weeks for a small bird to complete a full moult and during this period they can look incredibly scruffy. Any that do visit the feeders may look quite unusual, from yellowish blue-tits to speckle-headed blackbirds and fluffy robins that seem to have been dragged through a hedge backwards.
Beyond the obvious cosmetic changes, the annual moult presents a number of physical challenges. It’s a big strain on a bird’s resources, requiring a great deal of energy and plenty of protein, so they tend to avoid any unnecessary exertion. Shedding their downy layer of insulating feathers puts moulting birds at risk of catching a chill if night-time temperatures drop, and since their flight feathers must also be shed and regrown they are also more vulnerable to predation. In most cases they don’t lose all of their flight feathers at once (ducks, geese and swans being the notable exceptions) so can still fly but may lack their usual speed and agility. It also saps a lot more energy to fly without a full quota of feathers, so all things considered it’s sensible to stay out of sight. It won’t be long before the moult is complete and the birds are back in force, keen to fatten up on autumn’s bounty.