The unusual birds that summer in Israel and spend the winter in Russia
Israeli researcher stumbles upon endangered buzzard's unusual migration thanks to cutting-edge GPS transmitters purchased with the assistance of the JNF.
A Tel Aviv University doctoral student discovered a few weeks ago that come winter, the long-legged buzzard, an endangered raptor, heads north to Turkey and Russia instead of flying south to warmer climes like most of its feathered friends.
Gilad Friedman, who is doing his doctorate under the guidance of Dr. Yossi Leshem of Tel Aviv University and Prof. Ido Itzhaki of the University of Haifa, is studying the long-legged buzzard and the short-toed eagle in the Judean lowlands east of Kiryat Gat. He is to present his findings to the public for the first time at Tel Aviv University's annual ornithology conference later this month.
The long-legged buzzard has been a constant source of surprise for researchers in recent years. First they found that it, along with short-toed eagles, had begun nesting in trees in the Judean lowlands rather than in the desert. They believe the change is due to construction and forestation in more arid areas.
The question of where these raptors went in the summer has also mystified scholars. "Veteran ornithologists believed they remained in Israel year-round. But I couldn't find them between the end of June and the beginning of winter. Every time I got a report about a buzzard it turned out to be another species," Friedman said.
Friedman made his discovery of the unusual migration pattern of the long-legged buzzard thanks to cutting-edge GPS transmitters purchased with the assistance of the Jewish National Fund. He attached the transmitters to the backs of buzzards and short-toed eagles in the Judean lowlands. He also gave each bird a biblical name, choosing the names of David's wives for the females. Friedman says the new transmitters convey much more information, including speed and altitude. But they do not do so in real time, like the older satellite transmitters, and Friedman did not know where his subjects had disappeared to. He could only download the information from the transmitters when the birds were within a few kilometers of his location. "I waited half a year and bit my nails in anxiety," he said on Thursday.
A few weeks ago , Friedman went out into the field and suddenly began receiving data from the buzzards' transmitters. He was surprised to discover the birds were coming in from the north. Bathsheba the buzzard had flown in from Russia, while Abigail had been to Turkey. Michal, however, had wintered just a short hop away, in northern Syria.
The data confirms that the long-legged buzzards are migratory, nesting in Israel from November to June and then heading north for the winter, rather than south like other migratory avians.
It is the mass migration southward that fills Israeli skies with hundreds of millions of birds twice a year as they head south to Africa from Europe in the fall and back north to Europe in the spring.
"We know of only a few cases anywhere in the world of birds who fly north for the winter," Friedman says. "I can't explain the rare route the buzzards take; I suppose it might have to do with the availability of food. That's a very interesting question, because conditions in Russia, especially at the end of the period the birds are there, are quite difficult when it becomes very cold," he adds.
Leshem says the birds should be followed in Russia to find out exactly what they do there and whether, like certain species, they have two nesting cycles.
Friedman is also examining the relationship between the long-legged buzzard and the short-toed eagle, which have been nesting in the same region and competing for the same food sources.
"We know that sometimes the buzzards are more aggressive and chase the short-toed eagles out of nests they had used the previous year, which means the eagles have to build another one," says Friedman, who has photographed aerial battles between individuals from the two species.
Friedman has located more than 90 nests of both species, which tells him that the Judean lowlands offers them a good home. The habitats in the area, however, are under pressure from threats that include the establishment of new towns and roads.