The sound drifting from the pine tree outside the North Valley home of Brendan and Tria McCormack was impossible to ignore.

A giant swarm of bees had taken to the tree to do what bees do. But when a beekeeper arrived to analyze the situation, the bees decided to move on, and they did so by sundown.

"We had a bee guy come out, and he put some food out for the hive in one of those boxes," said Mr. McCormack. "It was some kind of jar. He's an old-timer and he really enjoys that stuff. He went into a long spiel on what the bees do."

That "old timer" is bus driver and long-time beekeeper Ralph Poe, who knows the ins and outs of bees as well as anyone in Helena.

Even Poe was impressed with the size of the swarm. He estimated the mound of bees to weigh as much as seven pounds - far more than what's available commercially.

"Normally, you don't find them in pine trees," said Poe. "You find them in the limb of a bush or the limb of a tree."

If a hive becomes too crowded, Poe said, the queen will take flight in search of a new home. The other bees follow and when she lands, they swarm around her to keep her safe and warm.

In the meantime, Poe continued, the scouts go searching for a hive. When they locate a potential home, they return to the colony and signal their finding. It is, Poe said, an intricate system with hierarchies and responsibilities.

The swarm outside the McCormack home pulsated in the tree, doing bee-like work. While some colonies around the country are struggling with collapse, threatening the nation's food supply, this particular colony looked to be thriving.

"The queen bee was in the center of this," said Mrs. McCormack. "The beekeeper said she must have just landed in the tree to find a new home or rest. She decided this wasn't her home."

"I've had wasps around and they're a bit more aggressive," Mr. McCormack added. "But the bees just kind of left us alone."

The congregation of bees grew larger, and so did the crowd drawn to the swarm. The McCormack's tree became a scientific marvel. Curiosity seekers came to witness the spectacle for themselves.

"They were amazed at the size and number of bees that were there," said Mrs. McCormack. "It was amazing. There were just thousands and thousands of them. Those who saw it couldn't believe the size of it. They'd never seen that many bees gathered together in one place."

Poe didn't have his bee suit with him when the swarm landed in the tree. He wanted to keep the bees, and so he placed a hive below the tree with some food in it.

"Sometimes the swarm will move into the box," he said. "I went back out that evening and they had just vanished. They must have found a suitable spot they wanted to stay in."

What does a swarm of bees sound like - when thousands of bees take flight at once?

"My daughter thought it was a truck driving off in our driveway," said Mrs. McCormack.

"They just took off and that was it," added Mr. McCormack. "They just disappeared."

Reporter Martin Kidston can be reached at 447-4086, or at mkidston@helenair.com