Every year, millions of birds that having finished breeding in the northern hemisphere, migrate south to escape the northern winter. Many species even cross the equator to get to South Africa. From large eagles to little warblers, swallows and swifts, they all make this incredible annual pilgrimage to their overwintering grounds.
One of the most spectacular and charismatic is the Amur Falcon. These little birds of prey arrive in South Africa in their hundreds of thousands around December and stay until late March. The entire population of the species breeds in the Amur region of the Russian/Chinese border of eastern Siberia, some 16 000 kilometres away. This means that these small falcons fly upwards of 40 000km a year – making them record holders for the furthest-migrating raptor!
You can see them sitting on telephone lines in grasslands and farmlands, where they provide a great service to farmers by hovering over fields and dipping every now and then to pluck juicy grasshoppers or caterpillars. At night, they congregate in “roosts” where they form a spectacular melée comprising thousands of birds. A count of some 38 000 birds was made in one roost in Newcastle, KwaZulu-Natal.
By tagging and ringing these birds, we’ve learnt that they undertake a remarkable marathon on the return leg of their journey. By fitting a tiny transmitter to the backs of a few birds, we discovered that they leave the eastern coast of Africa to fly non-stop for five days across the Indian Ocean and the Indian subcontinent, to arrive at a staging post in Nagaland in North East India, where they fatten up for the remaining leg of their journey.
Another marathoner that breeds in the same region, as well as across Northern Europe, is the willow warbler. This inconspicuous little bird, weighing just seven grams, also makes this impressive journey. Commonly heard in acacia trees in Johannesburg, this little insect eater is probably, gram for gram, the champ of migration.
And we couldn’t talk about migration without mentioning the swallow, particularly the barn swallow. This iconic bird – the subject of many fairytales – also undertakes the epic journey from northern Europe to the southern hemisphere every year. In fact, one barn swallow that was ringed on the South Coast, not far from Durban, was caught by another ringer in northern England just 16 days later!
The common swift is another remarkable species that breeds all the way from the United Kingdom to the Far East. This master of the sky will leave its nest as a youngster and not land at all for 10 months or more, sleeping and eating on the wing and only landing in bad weather. Even then, many swifts simply fly above it all. Some 30 birds were fitted with geolocators at the Summer Palace in Beijing, China by a group of researchers. The following year, when the swifts returned, the researchers caught 13 of them and downloaded the data. They were stunned to discover that the birds had flown to South Africa and back over a three-month period, with some birds flying 1 000km a day.
Another amazing candidate for the long-distance record is the bar-tailed godwit, which can be found along the shores of Africa after it finishes breeding in the high Arctic. One bird, tracked via satellite flying from Alaska to New Zealand, flew 11 800km non-stop in eight days.
The Arctic tern is generally believed to hold the migration record, however. This lovely little sea bird travels from Arctic Greenland, down over the Atlantic (it’s often seen off the coast of South Africa), south to the Weddell Sea in the Antarctic. It returns the following year. That’s a round trip of 60 000-80 000km. And if you consider that these birds live to between 15 and 30 years of age, this mileage could add up to three million kilometres in a lifetime, roughly the equivalent of four round trips to the Moon!
Of course, these incredible journeys are not made without their challenges. Migrating birds are at risk from hunting in the Mediterranean and Middle East, where thousands are shot each year as they pass through “bottlenecks”. They are also harvested for food in some areas and must contend with habitat loss, drought, storms and pollution.
So why do they do it you may ask? Well, if you are an insect-eating bird that has enjoyed a lovely summer in the Arctic circle with 24 hours of sunlight a day in which to do all your breeding and fattening up with relatively few predators, you may want to think about heading south when that cold weather starts to loom.
Ringing the birds
We know a lot about the individual movements of certain species thanks to bird ringing or banding. This is the practice of fitting a uniquely numbered metal ring to the bird’s leg or wing. The ring also holds the contact information of the ringer. By ringing birds we can find out about their movements, habitat preferences during migration, life expectancy, ratios of adults to young (to show breeding success or failure) and, ultimately, enable decisions to be made regarding the conservation of species based on findings from the collected data.
If you would like to experience the excitement of bird ringing in South Africa Malcolm Wilson facilitates outings between November and April, which range from day trips from Johannesburg to 14 day expeditions covering a huge variety of habitats. Visit: africanaffinity.co.uk.