Heron colonies: Majestic birds live the high life in treetop nests

With binoculars trained skyward, Donna Kostka scanned some distant alders for signs of movement.

We were perched on a pedestrian bridge over the Seattle-Everett rail line, an unlikely location for birding.

Sure enough, within a minute the prehistoric outline of a great blue heron was cast against a bruised sky as it made a short flight from one clump of trees to another. Here, yards away from busy railroad tracks, the Lake Washington Ship Canal, industry and a residential area, some 16 pairs of herons have formed a colony of nests on trees in the Kiwanis Ravine next to Discovery Park in Seattle.

Elsewhere around Puget Sound, including on Bainbridge Island and in Renton, great blue herons have created their aerial condos, apparently but not entirely oblivious to human activity nearby.

"People have different opinions on how calm you have to be," said Kostka, a former University of Wisconsin professor now retired to Puget Sound. "Some people say 'I've lived here 15 years and they don't flush easily.' We just don't know enough about these birds."

Partly to raise awareness about the plight of urban birds, Seattle Audubon Society conducted a poll last fall to nominate an official city bird. By a soaring majority over its closest rival, the crow, which, incidentally, enjoys stealing heron eggs, the great blue heron collected the most votes.

"The great blue heron is majestic and beautiful, like our city," said Seattle City Council President Peter Steinbrueck, who introduced a resolution to designate the heron as Seattle's official city bird. Mayor Greg Nickels signed the designation in a ceremony last month. The great blue heron is listed as a priority species by the Washington Department of Fish and Wildlife. This indicates its numbers are in decline but it is not afforded any legal protection.

Heron lovers such as Kostka hope the municipal designation will inspire acts of generosity towards the city's biggest heron colony, this ravine close to Discovery Park originally gifted to the city by the Kiwanis Club.

Look, up in the sky

Locally, the Kiwanis Ravine and the Black River Riparian Forest, a city park in Renton, are among the best places to view herons. The Renton site has more than 100 nests, and a colony on Bainbridge located on private land has some 30 nests. (See "If You Go" for details of local colonies and driving directions.)

A heron colony is quite a sight, with its nests of woven twigs high in the trees. Herons tend to nest 60 to 100 feet up, and in groups. Paired herons share the job of incubating their eggs, and protecting them from predators.

According to Lauren Braden, advocate for wildlife habitat with the Seattle Audubon Society, bald eagles are a factor when it comes to herons abandoning colonies.

"It's an emerging problem," said Braden. "As the bald eagle bounces back in population, the herons will get scared and all abandon their nests and the eagles will come in and take their babies. It was definitely a reason for losing the Duwamish Green Belt rookery."

In recent years, other colony sites have also been abandoned, though it's still not clear just what factors — natural or human — contribute to herons simply leaving their nests. Kostka and other volunteers involved with Heron Habitat Helpers, a group focused on the Kiwanis Ravine colony, are working with Audubon officials to get the city's planning and zoning codes amended to limit construction noise during heron nesting season.

"It wouldn't prevent activities taking place, it would just prevent loud noise during the three months that the herons are most sensitive," said Braden.

A special appeal

With their 4-foot-plus wingspan, spindle legs and black plumes that look like mascara above their eyes, herons have a special appeal for bird-watchers. It's even more fun to view their nest-building and mating rituals, though with the trees in spring bloom, it's getting too late in the year for that part of the heron life cycle.

But there's still lots of pleasurable viewing to be had — seeing them roost or go on foraging outings. And then there's their distinctive call — kraak, kraak, kraak — which sounds a bit like a laryngitis-sufferer trying to yell.

Once you've sighted a heron, it's easy to get hooked on the birds. "It's a good entry point for people to get interested in other birds and habitat and other kinds of nature," said Braden.

Gordon Black is a free-lance writer who lives on Bainbridge Island.