Nightingales in November (6 page)

After heavy snow, or during periods of hard frosts, many Lapwings from northern Britain tend to be either pushed towards south-west Britain or across to southern Ireland,
which tends to avoid the worst excesses of winter, thanks to the warming influence of the Gulf Stream. This contrasts with the many Lapwings that have bred in the southern half of Britain, which seem to respond to freezing conditions by simply abandoning the British Isles entirely. Crossing the English Channel, most of these birds will temporarily settle anywhere from coastal France all the way down to the Atlantic coasts of Spain and Portugal, before the ‘breeding imperative' draws them back to Britain later in the spring.

One bird that will refuse to budge from its territory, come rain, shine or even Arctic conditions, is the Tawny Owl. An established pair will rely on an intimate knowledge of their territory to eke out an existence even in the most severe of conditions. For those ‘Tawnies' that have set up home in more urban and suburban environments, recent research suggests that they take a higher proportion of birds in their diet, meaning their choice of food may well be easier to find after a covering of snow. This contrasts with many rural Tawnies, which mostly rely on small mammals for sustenance throughout the year, with Bank Vole and Wood Mouse being the two species most commonly encountered in the owls' pellets. Unlike many British mammals, the Bank Vole and Wood Mouse do not hibernate, but stay active all winter, with the Wood Mouse venturing out to forage mostly at night, while the Bank Vole will feed intermittently right around the clock. Snowy conditions, for example, can make hunting the owls' prey far more difficult, as the mice and voles will still be going about their business, but out of sight under the snow. In this situation, the Tawny Owls may supplement their diet with carrion from animals that have succumbed to wintry conditions. This was clearly demonstrated in the BBC's
Winterwatch
in January 2015,
where the team managed to film a Tawny Owl tucking into a deer carcass each night at the Mar Lodge Estate, within the Cairngorms National Park. Tawny Owls, it seems, are not just top predators, but supreme opportunists as well.

Harsh British winters can exact a toll on even the hardiest and most resilient of birds, such as Robins. With insects providing the bulk of its diet for most of the year, the Robin's ability to change to fruit and seeds during winter stands it in far better stead than birds such as Treecreepers and Dartford Warblers, which are confined to an insectivorous diet throughout the year. It will not just be the Robin's catholic diet that helps see it through any particularly cold periods, but also its willingness to take advantage of our love of feeding garden birds. Being so confiding by nature has enabled the resident Robin to often be first in the queue when it comes to dining out on any food we leave out on bird tables up and down the land.

Unlike the Robin, the holding of a territory is not an issue for Blue Tits in the winter, resulting in large numbers of individuals continuing to move through our gardens at this time of year. Frequently accompanied by other small birds, the majority of Blue Tits passing through will be local birds that have bred in neighbouring gardens or nearby woods, with a varying number of nomadic birds added to the mix. Most British Blue Tits are not thought to move more than a few kilometres from where they hatched, but by contrast continental Blue Tits are much more inclined to migrate in winter, even crossing the North Sea in some years. So for those with gardens on the east coast, there is every possibility that some of the birds seen feeding on peanuts or fat balls
could be Blue Tits of Belgian, Dutch, German, or even Norwegian descent.

While many Peregrines breeding in northern Europe, North America and Siberia will be forced to migrate south to find enough food to hunt, our comparatively mild winter climate means most British Peregrines will rarely have to move far from their nest site even when the temperatures drop. Although some upland Peregrines will move away from their breeding quarters as winter sets in, most urban pairs should be able to find enough feathered prey in and around their towns and cities to sustain them through to spring. Recent research carried out by Peregrine expert Ed Drewitt suggests that urban Peregrines might not just be hunting during the day, but are making a substantial number of kills through the night too. By examining prey remains, mostly in the form of feathers collected at well-established plucking sites, Ed has been able to reveal that Peregrines are taking a far wider range of food than just feral pigeons. Winter visitors to Britain such as Woodcock, Teal and Moorhen are also being taken at this time of year as they migrate across urban areas at night. Historically, these birds may well have formed a much smaller part of the Peregrine's diet; however, it is thought that as the light from street lamps and buildings shines into the night sky, this light pollution is illuminating them as they pass overhead.

While Peregrines are most commonly seen catching birds during the day with the stoop dive, which involves closing their wings and dropping out of the air at immense speeds to hit and hopefully kill outright their chosen quarry, at night they employ a totally different technique. Lurking in the shadows of a church or tower block, when an urban Peregrine spots the pale belly of a bird lit up like a light bulb, it only need fly a short distance upward to take the
bird unawares from below. Peregrines will also insure against any potential temporary shortages by storing excess food during times of plenty. In winter this means that any cached food will effectively be stored in the equivalent of a fridge freezer!

British-breeding Puffins, come the middle of January, will still be dispersed in a wide arc between the North Sea and the north-east Atlantic. As many birds are already in winter plumage by the end of August, they are thought to undergo a complete moult between late autumn and early spring to ensure they look freshly laundered by the time they arrive back at their breeding colonies the following spring. It's not clear exactly when the main flight feathers are replaced during the winter, but recoveries of dead Puffins either hunted or washed up ashore during this time seem to show that the moult is carried out in a synchronous fashion along each wing. While these feathers are growing the Puffins will become flightless, but despite an inability to take to the air, they are still able to dive and search for food. Presumably any Puffin still renewing its flight feathers at this stage will need to have made sure its chosen moult location will be able to provide enough food until its wings are finally ready for taking to the air as well as cutting through water.

Unlike the Puffin, which will be bobbing around out at sea like a cork for at least four to five weeks while moulting its flight feathers, our British Swallows down in South Africa will still be able to fly throughout their entire moult. Because Swallows obviously need to be able to fly efficiently in order to feed, the moult is a slow process which may take anywhere between four and a half and six and a half months.
The Swallow's body and head feathers are the first to moult, followed by those on the wings and tail. They must also moult the flight feathers in a symmetrical, ordered fashion along each wing to prevent any imbalance during flight and ensure their manoeuvrability is not impaired while feeding. With these feathers being replaced so gradually, it is quite normal for the outer primary and tail feathers to still be actively growing by the time the birds have begun their long spring migration back to Britain in around a month's time.