11-Aug Feathers and Flocks

Most moults are short and occur either during breeding, after, or before migrating or possibly when the bird reaches its winter quarters. Willow warblers are the rare exception undergoing two moults, one before they set off and then a second when they arrive. Swans, geese, grebes and ducks all tend to lose all their flight feathers at the same time and consequently for a short time they all become flightless. This is when we use the term ‘in eclipse’. Geese and swans tend to moult while their goslings and cygnets are small. Male mallards enter their eclipse in June but females wait until their ducklings are independent which may well be this month.

Many raptors have an almost continuous slow moult as they cannot afford for anything to interfere with their flying prowess. Female peregrines and sparrowhawks moult while they are feeding and protecting their young on the nest whereas the males, who need to fly to bring in food, wait a little longer. Gulls also vary as to when they lose their feathers. Herring gulls start in July and end in September, whereas lesser black-backed gulls wait until they reach their winter quarters. Larger gulls may take several years to gain their full adult plumage. This is why we see so many gulls with such a variety of different markings. August is a month when many birds may be in various stages of dress or undress as well as showing a variety of unusual colour combinations.

Flocks

In stubble fields flocks of starlings, sparrows and woodpigeons are all now a common sight. Occasionally these may include a jay or possibly even some linnets. Around the edge of London more noisy flocks of rooks and jackdaws are getting noticed more. In open fields flocks of lapwings sometimes overlap with groups of starlings and gulls. In London murders of crows are a common sight even in parks.

In gardens we tend to notice bands of tits possibly containing blue, coal, great and long-tailed tits. In such parties it is always worth looking out for marsh and willow tits which more rarely join them. In woods it is flocks of woodpigeons and chaffinches that are seen most often but there may well be smaller family groups of chiffchaff, willow warbler and possibly even tree creepers and goldcrests. Among groups of chaffinches it is always worth looking for redpolls.

Along the Thames estuary groups of waders are now moving south in every increasing numbers as the month progresses. Many of these will be small mixed flocks of redshank, curlew, godwits, sanderling, dunlin and knot. Birds that are occasionally in flocks of over one hundred or more include teal, mallard, shoveler, pochard and coot. Tufted ducks can sometimes reach astronomical numbers with over 2,500 having been recorded. London’s reservoirs and Barnes Wetland Centre are good places to look for such flocks. Massed roosts around the time of high tides provide one of the greatest spectacles of the month. In such situations raptors such as peregrine, hobby and marsh harriers are quite likely to make an appearance.

Arguably the most beautiful flocks, after the vast congregations of waders, are those of swallows and martins whose numbers are now starting to build up on telegraph wires. Good weather and a suitable wind will result in them all disappearing south. Rarer flocks this months include thrushes, pied flycatchers, spotted flycatchers and yellow wagtails. Yellow wagtails tend to roost together at night and a flock of 400 or more was recorded at Coalhouse Fort in 2001 proving these rare events still occur.

Flocks of turtle doves and shrikes now seem stories from the past. Because of their sudden disappearance overnight, turtle doves were at one time thought to change into stock doves and for similar reasons redstarts into bramblings. London’s Victorian bird catchers used to focus on these flocks, trapping birds to cage and then sell them. Favourites were goldfinches and linnets. Linnets were then occasionally caged with canaries to improve their song and goldfinches were either blinded or had their tongues barbarically split to improve their soft ramblings.