Western river-runners who come upon a great blue heron along the banks invariably end up playing an accidental game of hide-and-seek with the majestic but awkward bird.

Western river-runners who come upon a great blue heron along the banks invariably end up playing an accidental game of hide-and-seek with the majestic but awkward bird.

After standing motionless as a boater floats toward it, the nervous heron bolts to the sky and flies downstream, afraid it's being stalked. Moments later, as the boat again approaches, the heron considers its fears validated and flies farther downstream, only to repeat this paranoid hopscotching again and again until it finally figures out it should fly upstream to apparent safety.

"You'd think they'd fly behind you, but they always fly in front of you," says Karen Hussey, research and monitoring program manager of the Klamath Bird Observatory in Ashland.

Though the heron's suspicious mind-set is well known in the birding world, no one knows just how many of these anxious birds are out there.

But federal biologists across the West are about to find out. With the help of organizations like the observatory, they are fanning out across Oregon and 10 other states to quantify the known nesting sites, called rookeries, of herons and a cache of other colony-nesting birds that have had no real census.

The KBO will survey about 200 areas statewide for herons, egrets, white pelicans, cormorants, Caspian terns and two sub-species of gulls in what is the U.S. Fish and Wildlife Service's first attempt to gauge the relative health of the birds.

Counting known breeding pairs during the spring nesting season will provide base-line data which, when compared to historical data and future surveys at these same sites, will offer insights into whether these birds are trending up or down over time.

"This is a snapshot in time," says Jenny Hoskins, a fish and wildlife service biologist overseeing the Oregon part of the survey. "It gives us a starting point, base-line data, of what's out there."

The data will help federal biologists make management decisions about these birds and help resolve potential conflicts between birds and people, Hoskins says.

It can even quantify such things as how expanding populations of bald eagles are affecting herons, which eagles tend to chase away from their nesting grounds, she says.

"We've done surveys in bits and pieces, here and there," Hoskins says. "This is the first real comprehensive survey on them."

Over time, biologists hope to estimate the minimum regional population size of the waterbirds in the 11 Western states and produce an atlas of breeding colonies in 2012, Hoskins says.

This is the third year of the surveys, which cost a little more than $1 million and include some in-kind services and staff time from various state wildlife agencies and conservation organizations, Hoskins says.

"There are some large-scale information gaps and we're all filling them in together on a local level," Hussey says.

KBO has about a $109,000 contract for its efforts here, which will include surveys at seven Jackson County sites.

They include two well-known heron rookeries — one on the Rogue River across from TouVelle State Park and another in the Kelly Slough area drained by last fall's removal of Gold Ray Dam from the Rogue.

Great blue herons are largely solitary creatures until spring, when they nest and breed in rookeries that consist of individual nests often in oak stands high above rivers or streams.

The herons are in the middle of their nest-building, courtship and breeding, which typically last through April.

Birds fly in and out of the rookeries regularly, with others perched on thin branches that sway in the spring breeze.

The TouVelle-area birds are easily spotted and viewed with binoculars, especially in early spring before leaves camouflage the nests, Hussey says.

Hussey says KBO teams will survey the various sites through May and June, when breeding pairs will be easily spotted.

Mark Freeman is a reporter for the Mail Tribune. Reach him at 541-776-4470, or email at mfreeman@mailtribune.com.