There's a new breed of Canada goose afoot, or aflight. Call it the Northern Virginia Canada goose.

Drive out Rte. 50 or Rte. 7 or Rte. 66 any day this spring and you are likely to see Canadas flying, nesting or raising young goslings.

They are in farm ponds, on public lakes, in people's yards and on golf courses, chewing up the greens.

The man who has watched this flock grow over the last three decades from a few pairs of domestic geese says the Northern Virginia flock today is indistinguishable from wild birds that migrate to and from Canada. But these birds live here year-round and will continue to do so as long as they continue to procreate.

The flock, he says, gets bigger every year.

The expert on this population boom is Byron Wates, who retired five years ago from his job as a landscape contractor in Fairfax.

Today he lives in Cambridge, Md., where he raises rare and exotic waterfowl, mostly for fun, on his propagation farm.

Years ago he became interested in the increasing numbers of Canada geese he saw in his work around Fairfax. After some years he determined he could trace the entire flock that existed at that time to one source.

"After World War II a man named Michael Straight had a farm in Anandale. He built a couple of ponds on it, and bought a pair of Canada geese from a professional propagator like me," Wates said.

This first pair of geese had their wings pinioned so they couldn't fly. But their offspring were allowed to fly free.

"Canadas mature sexually in about three years," Wates said. "Geese are territorial when they are nesting, so the older pair would chase off their offspring when the young birds tried to nest in the same ponds."

"So the young geese took off, starting the spread to other nearby ponds."

It wasn't long before a significant population began to develop in Northern Virginia. In the fall the birds would gather to spend the winter in flocks. One of the first places they chose to inhabit in large numbers, Wates said, was Lake Barcroft.

Residents there didn't care much for geese all over their community, and in response to their complaints the Virginia Game Commission trapped and transferred great numbers of geese to Back Bay near Norfolk, Wates said.

But they missed a few, and the cycle began again.

Wates became involved in helping the flock along the second time around. He discovered the mature geese were having trouble raising goslings because of excessive predation and trouble from youngsters pestering the nesting adults on farm panels.

In the early 1960s he fashioned some floating nest structures out of oil drums and installed them on five farm ponds the geese were using near Burke Lake.

It worked, and he said that since then the flock has prospered.

"One spring we brought off 31 goslings on those five ponds," Wates said.

"About that time I obtained a permit to band some of the local birds. What we found from banding and collecting was that whenever the ponds got saturated with nesting pairs, the birds would spread to new areas."

And so it has gone. Wates guesses that today the "Fairfax flock," as he calls it, numbers about 300 birds. But this research showed that another flock was growing in the same fashion southwest of that area with its roots probably in a pair of domestic birds kept around Charlottesville.

And the U.S. Fish and Wildlife Service started a third flock some years ago at its Patuxent Research Center in Laurel.

Wates believes the flocks have now grown to the point that the birds from all three are intermingling.

The "Fairfax flock" has kin now in Prince George's, Montgomery, Loudoun and Prince William counties and elsewhere around the metropolitan area.

Matt Perry of the Patuxent research facility said, "If you could get figures on it, you'd probably see a precipitous increase in Canada geese on urban and suburban ponds in the area in the last 10 to 20 years.

"This does not reflect a change in goose habits," he said. Canadian geese are still migrating yearly to the far north. They haven't changed their ways.

The local geese follow the same instincts as the ones which fly back to Canada each spring, Perry said. They are seeking nesting areas as close to where they were hatched and raised as they can get.

The range keeps growing. "Seems like every farm pond around here has a pair of Canadas in it this spring," said T. A. Daniel, game warden in Loudoun County.

Wates reckons it'll just keep going on. "In my opinion, man can do what he wants to the environment. But Canadas will survive."