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Photo: Kristaps Sokolovskis
The little leaf singer, the most widespread bird in Sweden, is a very long haul. The birds of northeastern Russia move to East Africa. A distance of 1,300 miles, easy route.
The most common bird in Sweden, the little leaf singer, is a record-size pilot. Because when their peers in the north-east of Russia move, they are warned. Then they fly no less than 1,300 miles of easy road.
"It's clearly a record for this weight class," said Professor Susanne Åkesson.
With Russian colleagues, Swedish researchers have studied the leaf singer, a small gröngul bird, as well as the most widespread in Sweden. The bird is mainly observed with the help of his song, which begins with high tones, and then is rounded off by "a graceful musical gesture disappearing into nothing," according to the expert.
"Normally they weigh eight to nine grams, maybe 10, but not much more," said Susanne Åkesson, a professor of zoology at Lund University.
Scientists have known for a long time that this bird goes far, but not exactly in what distance or which route he chooses. To find out more, scientists are attaching a small set of 29 lions isolated in Magadan, near the Kamtjatka Peninsula in northeastern Russia.
Measuring light
The equipment records daylight every five minutes. As the length of the day varies, researchers can determine where the bird is in the north-south direction. By throwing a bell when the birds are released, the researchers can also see the day of driving relative to the starting point, thus calculating, if necessary, the movement of the bird in the west-east direction.
"This will not be accurate, but we will do enough to say something about the location of the bird," said Susanne Åkesson.
TT: Why do not you use the GPS?
– This equipment is too big.
A year later, the scientists managed to capture four of the birds, three of which provided data. It turned out that the psalmists had traveled at least 1,300 miles, easy route.
– Probably, it will move even longer, but the batteries will finish. It was as far as we could measure, "said Susanne Åkesson.
Favorable movement
First, the trip had traveled to Southwest Asia and the eastern Mediterranean where they had stayed for a few weeks. After that, they went to their winter quarters in Kenya and Tanzania.
"It's an extremely long movement and a record for such a small bird," said Susanne Åkesson.
The move started in late August and the birds only arrived in East Africa in December. But it's not the flight itself that takes time. For each flight day, the bird must rest for seven hours to be able to take enough fat. So it's refueling that takes time.
TT: Why are birds moving so far?
– They are insecticides and Kamtjatka is not very good in winter. Moving up to here is expensive, but studies have shown that it may not have been as expensive as before. An alternative is to stay in Africa, but in the tropics, competition is much greater. There are more predators and diseases. In addition, Africa also experiences seasonal variations. Several factors have therefore favored the movement of some birds so far, "said Susanne Åkesson.
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