Nightingales in November (17 page)

While our Nightingales are busy leapfrogging their way to southern Europe, mid-March sees most British-breeding Cuckoos resting and feeding up at a diverse range of locations centred around Ghana. A number of the satellite-tagged birds, including ‘Cuckoo Chris' have at some point dropped in to Digya National Park, situated in the east of the country, but on the west bank of Lake Volta, the largest reservoir in the world. Digya is the second largest national park in Ghana, and situated on a lowland peninsula that mostly consists of transitional habitat between forest and savanna. So having spent the winter possibly feeding alongside gorillas, the Cuckoos will now be fattening up close to elephants as they prepare to negotiate North Africa and the mighty Sahara.

Both the spring and autumn migratory routes and the overwintering destinations of British-breeding Cuckoos in Africa.

Further north our intrepid Swallows will have just crossed the semi-arid habitat of the Sahel, a region that straddles the
entire continent in a broad band between Senegal in the east and Ethiopia in the west. So by mid-March they should be girding their loins in preparation for taking on the largest hot desert in the world. Extending over nine million square kilometres, and covering a quarter of the entire African continent, the huge landforms of the Sahara Desert are shaped by both the wind and rainfall from a more fertile era. Consisting of sand dunes, sand seas, stone plateaus, dry valleys, dry lakes and salt flats, the Sahara Desert has to be one of the most inhospitable places on Earth. It is also believed to he too much of a detour for the Swallows to follow the return route of the more westerly-wintering Nightingales, meaning they will have no choice other than to engage the desert head on if they're to reach the insect-rich summer of northern Europe. Having fed the whole way since leaving South Africa a month before, it's highly
likely that the lack of vegetation, relentless sun and strong winds will mean that invertebrates over the desert are few and far between. So as the Swallows pass through Mali and Niger and on to the huge desert country of Algeria, they will just have to trust that their limited fat reserves will see them through beyond the sand to the rich coastal crescent of North Africa.

While the Sahara Desert and the Mediterranean Sea are reached much earlier during the southbound migration in autumn, the return spring journey is a different story. Travelling north, the two immovable obstacles of sand and sea will come much later in the journey, and only after the birds have already flown several thousand kilometres across Africa. Doubtless the passage across this hugely inhospitable terrain must be physically very stressful, with innumerable Swallows perishing in the sand before the stronger and more experienced birds finally straggle into the coastal feeding areas of Algeria, Tunisia and Morocco.

There are few recorded sightings of Swallows in the Sahara itself and the 1,500km distance across the desert expanse will surely be the most gruelling five or six days of their year. Possibly flying for up to 14 or 16 hours a day, the Swallows must presumably roost wherever they are able, before the breeding imperative drives them on at dawn the following day.

Of the total of 35 Waxwings caught and ringed while overwintering in Britain only to then be subsequently recovered abroad, 27 were found across Denmark, Norway, Sweden and Finland. The fact that these birds were found in a diverse array of locations across Norway, Sweden and Finland is perhaps no surprise, as these will almost certainly be records of birds either close to, or at their breeding
grounds, but the six from Denmark is in many ways more revealing. Waxwing as a species doesn't breed in Denmark, so this would suggest that any British-ringed birds observed must be en route, thereby revealing the main route that returning birds will take on their way to northern Scandinavia and the Russia Federation. With many Waxwings already having left it's perhaps surprising, even in a poor year, how a number will still be happily to feeding in Britain late into April. These late leavers must then presumably make a much quicker return to their breeding grounds than those that left earlier in the year.

From now on, Britain should be a Bewick's free zone until the first birds begin returning in the autumn. Having reached Denmark, Germany, Poland and southern Sweden in one hop it seems that many of our Bewick's are in no hurry to reach the Russian maritime tundra, which will certainly still be frozen over at this time of year. With seemingly plenty of food still available in northern Europe, satellite tracking data from the WWT indicate that some of the Bewick's Swans will not have moved far from their first arrival point. Other birds, however, will have begun to slowly spread out along the Baltic coast, passing through Poland, Lithuania and Latvia on their way to internationally important stopover locations in Estonia.

Late March

Finally emerging from the Sahara, only to then hit the Atlas Mountains, extending some 2,500km in a south-westerly to north-easterly direction through Morocco, Algeria and Tunisia, conditions for the Swallows should suddenly begin
improving as they catch sight of the Mediterranean Sea way off in the distance. As the birds drop down towards the coast, the Aleppo Pines and Evergreen Oaks of the mountain forests will soon give way to Mediterranean-type scrub, called maquis, and a welcome change of climate. For those Swallows that haven't either perished in dust storms, or fallen from the sky due to exhaustion or a lack of water, the cooler temperatures and higher rainfall encountered all along Africa's north coast will not have come a moment too soon.

The believed spring and autumn migratory routes of Swallows between their breeding grounds in Britain and north Africa.

Exhausted from their efforts, and with many Swallows having lost a third of their body weight, they will need to feed up quickly before then crossing the Mediterranean Sea and arriving in Europe along a broad front, anywhere from the eastern coast of Spain to western Italian shores. Finally back over dry land, for those birds that took the more westerly
route, sites such as the Ebro Delta, situated between Valencia and Barcelona, will represent an important refuelling station. Quickly moving on towards the Pyrenees, these Swallows will then begin streaming across the autonomous community of Aragon in the north-east of Spain. With Aragon's northern boundary forming the border with France, and positioned in the middle of the mountain chain, the Aragonese say that ‘the Swallow is the bird that melts the snow', as the birds work their way east to west, through mountain valleys flushed with melt water. By the time they reach the Bay of Biscay and the French coast, the Swallows should be spurred on in the knowledge that they're on the home straight.