Huge flocks of synchronized starlings that appear like a black cloud are returning to Israel for the first time in 20 years, according to ornithologist Dr. Yossi Leshem of Tel Aviv University.

The common starling, first sighted this year at Kibbutz Ein Gev on the eastern shore of the Kinneret, used to fly to Israel from Russia and Eastern Europe until about 20 years ago in mind-boggling flocks numbering some 15 million. But for unknown reasons, the population declined to about a tenth of its former size, and for that reason is no longer seen in Israel.

But now that their numbers are climbing back, they can now be sighted again in Israel, particularly at dusk when the flocks begin their spectacular aerobatic display before retiring for the night.

According to Leshem, of the Society for the Protection of Nature in Israel, "after spending all day in the fields, the starlings gather for about 20 minutes of amazing aerial antics." The larger flocks create a black cloud that without warning changes direction and form, in a sychronization that is difficult to explain, he adds.

Leshem says the birds' communal behavior reveals something of what he calls its "wisdom."

"If it would be every bird for itself, they would be immediately devoured as prey, while in a flock of half a million, they protect each other," he says.

More than likely the flock protects itself in this way from raptors trying to cull individual birds, because the raptor can't zero in on a single starling, Leshem explains.

The airborne community has another advantage vis a vis its natural enemies, Leshem says: "In a split second, the flock that was a flying ball only a moment before changes direction and the burst of wind flips the raptor over on its back," he says.

However, not everyone is a fan of the huge flocks. At Kibbutz Ein Gev, for example, the starlings consume large amounts of animal feed and drop into the dining room uninvited.

Speaking of dropping in, the droppings such a huge flock leaves after an overnight stay are also less than welcome, the kibbutziks say. It was this aspect of the starlings' communal visits that led to keeping them permanently out of Hamat Gader, one of the best-known of the starlings' overnight spots in old days before it became a tourist attraction.

"Twenty years ago we'd walk around with umbrellas to protect ourselves. I hope we're not going back to that," an Ein Gev kibbutznik says.