GoKawiilThe scientific mystery of how songbirds from one population are able to join other members of their own population at the same winter destinations following their long solo migration has been answered.
In a groundbreaking new study published in the journal Science, researchers have found that a combination of genetics and environment determines where migratory birds fly to for the winter.
By attaching tiny data loggers attached as backpacks to pied flycatchers, the team was able to record the birds’ routes over thousands of miles across land and sea.
This revealed that birds in different areas of Europe follow consistent routes to their wintering spots in Africa even when they are not the most direct.
The research was conducted by a team of European scientists led by the University of Groningen, and featuring the University of Exeter.
“Every autumn, billions of migratory birds leave their breeding areas to fly thousands of kilometres to warmer winter locations,” said Dr Malcolm Burgess, of the Centre for Ecology & Conservation at the University of Exeter, Cornwall. “In species such as geese, young birds learn migration routes from their parents, while in some other species they learn from companions with whom they migrate. But for songbirds that migrate at night, it is unknown what causes them to choose a particular place.”
The research team used incredibly light data logger trackers measuring light intensity and time fitted as backpacks to the birds. The birds were tracked from eight areas, ranging between Spain and Siberia – with Dartmoor the focus of the UK work. When the birds were recaptured, the team read the data to estimate the path they took and how long it took them to make their journey.
The results showed that in the autumn, all populations first flew to Spain and Portugal. There they made a longer stopover, before continuing in a non-stop flight of around 40 hours across the Atlantic Ocean to the westernmost tip of Africa.
Their migration routes then bent eastwards, with birds of different populations continuing their journey for varying distances: the Spanish birds settled in the westernmost part of the wintering range, whereas the Siberian birds flew 3,000 kilometres eastwards to spend the winter in Nigeria. While the Spanish breeding birds flew only 3,000 kilometres in autumn, the Siberian birds covered almost 13,000 kilometres because of the long detour they make via Spain and Portugal.
“It is not only remarkable that a small bird weighing just 12 grams covers such distances, but also striking that pied flycatchers from Siberia take such a long detour,” said Dr Burgess. “A more direct, less westerly route, in which birds cross the Mediterranean Sea via Italy and then fly over the Sahara, would save them about 4,500 kilometres and is used by a closely related species, the collared flycatcher.
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