But for the tens of millions of these birds, this autumn's journey could be the most perilous they have ever faced. Many will not live to return here in the spring.
Millions face early death because of a dramatic increase in the dangers posed by global warming, loss of traditional feeding and nesting grounds, massive use of pesticides and an even greater threat from hunting.
The challenges are so great, The Independent on Sunday can reveal, that ministers will call for a global effort to protect migrating species at a meeting of Europe's senior naturalists in Aviemore, Scotland, next week. Experts at the British Trust for Ornithology (BTO) have added to the sense of urgency by warning that Britain's migratory birds face far tougher challenges than ever before as they fly up to 10,000km to reach winter nesting grounds.
This year's unusually hot summer has dried up the regions of Spain and Portugal used by swallows and reed warblers for "pit stops", drastically cutting food supplies. Across the Mediterranean, the Sahara is spreading south by up to 100km a year, presenting an even more formidable obstacle to cross.
Food supplies south of the Sahara are being hit by falls in water supplies and a drier climate, while in central African countries such as Nigeria, villagers trap hundreds of thousands of migrating birds, including swallows, for food.
Farming pressures - such as the introduction of monoculture cash crops and heavy use of pesticides - are also leading to massive changes in local habitats.
Wetlands in West Africa where sedge warblers nest are being drained for farmland. In Senegal, acacia woodlands where turtle doves roost are being chopped down for charcoal, while in Ghana, the tropical forest is 25 per cent of its original size.
Even in Europe, where millions of migrating birds such as turtle doves and cuckoos are shot for sport each year in France, Italy and Spain, agricultural changes are having an impact. The move by British supermarkets and wine suppliers to use plastic corks and screw tops has lead to cork plantations in Spain and Portugal being uprooted, posing a major threat to the pied flycatchers that rely heavily on Iberian cork oaks. On their journey home next spring, these species will face another new obstacle: northerly winds are getting heavier and more unpredictable.
Jim Knight, the UK's wildlife minister, told The Independent on Sunday that wildlife agencies across the EU must find new ways of coping with the impact of climate change on migratory birds and animals as they "seem to be especially vulnerable".
Dr Martin Fowlie, an ornithologist at the BTO, said: "These birds ... will travel thousands of miles to find nesting grounds and food. Even given perfect conditions, it's still an incredible undertaking. But recently, it has become far more difficult."
Swallow: flies to South Africa
Takes three months to fly the 6,000 miles to South Africa, but faces "desiccated" feeding grounds in Spain, a widening Sahara, and being trapped for food in central Africa. In South Africa, pesticides, crop intensification and water scarcity hit food supplies. Next spring, it will compete against stronger northerly winds
Turtle Dove: flies to central Africa
Must fly more than 2,500 miles. Since 1967 numbers have fallen 77 per cent. Up to four million are shot in southern Europe. Acacia forests in Senegal where it nests are being burnt for charcoal
Pied flycatcher: flies to West Africa
On its 3,000-mile flight, it will find cork oaks in its Portuguese feeding grounds and forests in its African nesting grounds disappearing. Numbers have fallen by 43 per cent since the late 1960s
Reed warbler: flies to Mauritania
This tiny bird flies some 3,500 miles to Mauritania and Guinea-Bissau, and faces scarcity of land and water in Portugal. Has to survive the Sahara, and then loss of food from modern farming in Africa
Sedge warbler: flies to West Africa
This water-lover flies about 3,500 miles to Mali, Senegal and Ghana but is under threat as rainfall declines and wetlands are drained for farmland and housing. Numbers are down 19 per cent from 1967
Cuckoo: flies to central Africa
Flies about 5,500 miles to winter in Africa. Numbers have fallen by 56 per cent since 1967. Modern farming and hunting are blamed, while earlier springs in the UK mean breeding time is cutReuse content