About 150,000 bees living high above the store-studded streets collect pollen from city plants, including from the grounds of the Imperial Palace and nearby Hibiya Park. (See photos of the Imperial Palace.)
As part of the project, the group sells about 660 pounds (300 kilograms) of honey each year, invites groups up to visit the hives, and take notes on unusual bee behaviors.
According to group chair Kazuo Takayasu, their observations suggest that using bees to battle crows will turn out to be an effective solution.
"We spoke to an expert and learned that honeybees in the wild have the natural response of attacking a black object that comes near to their hive," Takayasu said.
"There have been tests with black and white balloons, and the bees always attack the black balloon."
It is believed that the bees' reaction is linked to the color of bears' fur. The insects apparently attack dark-colored creatures to protect their hives from plunder.
"We noticed that the bees swarmed around crows that were taking offerings from white plates left on the outdoor altar of a shrine in Ginza," Takayasu added.
(Read related news: "Bee Buzz Scares off African Elephants" [October 9, 2007].)
"After a while the crows stopped coming back, so we thought it was worth trying at the terns' nesting site."
Between July and November of last year, two hives were placed on the roof of the Morigasaki Water Reclamation Plant to protect the birds once they arrived in April, and another hive was added this May.
Around 20,000 honeybees currently patrol the terns' nests, according to Masuda of the Little Tern Project, who added that the two creatures are getting on "like good neighbors."
"It is not 100 percent foolproof yet, because the area is quite large, and there do seem to have been fewer birds here this year so far," he said.
"But we are hopeful that it will prove effective over the long term."
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