Nightingales in November (62 page)

The believed autumn and spring migratory routes of Nightingales between their stopover sites in southern Europe and overwintering destinations in west Africa.

The topography of the country is generally considered fairly flat, with vast arid plains broken by occasional ridges and
cliff-like outcrops. To the west, between the Atlantic Ocean and the higher desert plateaus, the land alternates between clay plains and sand dunes, or ergs, some of which can become mobile during high winds. Following the Atlantic Coastal Flyway, which is considered a key route for many migratory birds moving between Europe and Africa, the Nightingales in early November are still believed to be steadily working their way along this route, represented along this particular stretch by the ‘thin green line' of the Atlantic coastal desert. As the birds advance further south, their move into the semi-arid savanna close to the border with Senegal will bring a measure of relief for the Nightingales, as the marginally higher annual rainfall closer to the equator enables the desert scrub to become steadily replaced by wooded grassland and bushland.

Over 4,000km to the south-east, the annual rainfall of around 180cm experienced in the Congolian swamp forests will find the Cuckoos experiencing a somewhat different climate to the Nightingales currently working their way along Mauritania's arid coast. Undoubtedly keeping a low profile in these wet, humid forests, the Cuckoos will not be the sole British-breeding representative to spend winter in the heart of Africa, as Swifts have recently been revealed through geolocator technology to spend most of their winter in the Congo too. Adopting a somewhat higher profile - and niche - than the Cuckoos, the Swifts will spend most of the winter months sailing above the canopy as they take advantage of the abundant insect life emanating from these incredibly diverse forests.

Certainly the contrast in habitat type could not be any greater than between where Cuckoos and Puffins will
choose to spend their winter. Weighing in at just under 400g, and only marginally larger than a pint pot, most British-breeding Puffins at this time of year will be at the mercy of the North Atlantic as they spend most of the daylight hours diving for dinner. How far Puffins disperse after leaving their breeding grounds was very poorly understood until Mike Harris's team on the Isle of May began to follow the movements of 13 birds with the help of geolocators. The first revelation was that ten of the tagged Puffins, upon leaving their breeding colony on Scotland's east coast, didn't stay in the North Sea, but immediately travelled anti-clockwise around Scotland's north coast to head out into the Atlantic Ocean. At some point during the winter all Puffins will spend four to five weeks with their wings effectively clipped as they moult their primaries, but this didn't restrict one tagged individual, ‘bird 6539', travelling an estimated 3,000km during an extensive tour of the north-east Atlantic during the winter months. Initially heading up to the waters around the Faroe Islands, this bird subsequently travelled down to the west of Ireland in early November, before then returning further north, presumably after having moulted its primaries, to spend time off St Kilda. Although many of the Puffins followed did not travel as widely as this adventurous individual, it's likely that many birds may well be covering a much wider area of ocean during the winter months than was previously thought.

As Puffins undertake expansive voyages out at sea, the adult Tawny Owl's entire universe will be the territory currently being vociferously secured for the winter and the breeding season beyond. The size of territory tends to depend on the quality of the habitat, with an established pair in mature, high-quality woodland often possessing a much smaller piece of real estate compared to those Tawnies living in
either open woodland, or farmland containing small isolated patches of forest. In studies made in and around the intensively researched Wytham Woods near Oxford, the Tawny Owls living in the deciduous woodland were found to occupy a territory, on average, of around 18 ha, while pairs living nearby in mixed farmland needed a territory of around double the size. Clearly, in the world of the Tawny Owl, territories are all about quality not quantity. Additionally, the boundaries between prime territories can often stay remarkably stable between years, even remaining fixed despite changes in ownerships as established birds either die of natural causes or become ousted by any young pretenders waiting in the wings.

With Robins also considered to be strongly territorial at this time, it is perhaps a surprise that Robins have been found to roost communally at some locations. After a roost was discovered in Aberdeen, further searching revealed five more around the city, with the largest gathering holding 53 different individuals throughout the season. By netting and colour-ringing birds using these roosts, the Robins were tracked down to breeding territories in local woodlands, which were patently exchanged in the autumn for different territories in nearby housing estates. While yielding more than enough food throughout the winter, thanks primarily to the generosity of householders leaving out food, it seems these urban territories may not be in a position to provide a sufficient number of roosting sites, hence the reason for the birds grouping together. Communal roosts have also since been located in Cambridge, where it was thought that many of the participating Robins were young birds unsuccessful in securing a territory in the autumn. Using these communal roosts may enable any newcomers to get the feel of the local situation on the ground, empowering them either to stay on in the hope of ultimately
gaining a territory, or simply moving on elsewhere if they considered the surrounding areas overly congested.

Keeping rigidly on territory wherever possible, each Kingfisher will defend its patch throughout the winter as if its life depended on it, which for once is not hyperbole. Certainly in the breeding season, territories can vary from a couple of hundred metres to a few kilometres of riverbank or lake perimeter in length, but winter territories generally tend to be smaller. Within that territory, most of the birds' activity will in fact be mostly confined to an even smaller core area, containing both good fishing spots and suitable roosting locations, as they knuckle down to the serious matter of seeing out the winter.

More confined to a home range rather than a territory, which they'll share with a motley band of other bird species by day, Blue Tits will normally prefer to spend their nights in a far more solitary fashion. Having such a small body mass can make surviving the long winter nights a tough ordeal, so the Blue Tits' technique for keeping themselves warm at night involves finding accommodation in the form of sheltered nooks and crannies. Keen to conserve energy by reducing heat loss means these tight spots may well be at a premium, with the result that any Blue Tit already occupying a favoured location as dusk approaches should easily be able to drive away any other bird attempting to gatecrash this party for one.