Maddox Woods rookery puts on a fine nesting show
It's kind of romantic, when you think about it. Every year around Valentine's Day the great blue herons return to the misleadingly named Goat Island in the Willamette River in West Linn, to find a mate and build a nest to rear their young through early summer.
"It's quite a show," says Marla Gaarenstroom, a West Linn resident who lives nearby. "The males arrive first to claim a nest or a spot to build one and they get busy trying to persuade a female to bond with them. It's a wonderful ritual — they clack their bills together, spread their wings — and he might move from spot to spot trying to find the perfect location."
Goat Island sits at the confluence of the Clackamas River. According to the U.S. Gazetteer, during the region's steamship era goats were kept on the island to keep vegetation down so there would be no visual blockages for steamship captains passing through nearby rapids on the Willamette.
Today, most of Goat Island's 23 acres is covered in brambles and ivy, discouraging human visitors but providing a nice oasis for waterfowl.
According to a 2014 report authored by Joe Liebezeit, staff biologist with the Audubon Society of Portland, while great blue herons are very sensitive to disturbances near their rookeries (nest colonies), it is possible for them to coexist with humans in urban environments and in fact the Portland metro area has several large rookeries. In 2014 citizen scientists counted 67 active nests on Goat Island, more than any other in the metro rookeries.
"Great blue herons are resident birds in the Northwest, they don't migrate," says Liebezeit. "When they aren't at the nesting sites they are in the region, out foraging in shallow water areas or sometimes in agricultural fields. They'll roost together at night but live independently."
While herons formed a rookery on Goat Island many years ago, supporting at many as 90 mated pairs in a single season, it's only been a few years that formal "Heron Watch" events have been held. Gaarenstroom became interested in the idea after discovering a "learning to live with wildlife" program held to help neighbors with resident beavers. Herons aren't as destructive as tree-felling beavers but they are fond of fishing in backyard ponds and learning to co-exist and appreciate these avian neighbors seemed like a good idea to Gaarenstroom.
"I'm a member of Friends of Maddax Woods and one of our missions is to provide educational opportunities to learn about the nature of the Woods (Goat Island is directly adjacent to the city-owned Maddax Woods Nature Park)," she says. "I helped our former president when he worked with local kindergarteners, teaching them about being good stewards of nature and it inspired me."
Gaardenstroom invited Liebezeit to give a presentation about great blue herons and organized a viewing from Maddax Woods afterwards.
Since 2015 there have been a handful of heron watches at Maddax Woods every winter/spring (once the trees leaf out it becomes difficult to view the herons in nests). This year Friends of Maddax Woods were given a grant from the City of West Linn to expand the program and they are focusing on interactive aids to interest children. Last year they built life-size wearable heron wings so kids (and their parents) could try them on for size to see just how large these unlikely-looking fliers are.
The group also has piles of sticks on hand so homo sapiens can try their luck at building a nest and life-sized photos of young herons so kids can see how they measure up.
Find out more
In June, the Audobon Society of Portland and Urban Greenspaces Institute will host a series of "Heron Week" activities; by May details should be available at audobanportland.org.
"The nests are far away enough it's hard to get a sense for how large the birds are," says Gaardenstroom, although she adds that the birds often fly right by the viewing platform on their way to and from gathering sticks or fishing.
Eggs start hatching a month or so after mating, according to Gaardenstroom, and the fledglings start roaming within two months.
"They don't leave right away," she says. "They stand on the branches and learn to fish. It's fun to watch them learning because they are pretty awkward at first. It takes them awhile."
According to Oregon Fish and Wildlife Department, while late winter is the best time to see the herons' mating rituals and nest building, late spring and early summer can be just as entertaining, as young herons compete with their nest-mates for food brought by parents and make a great show of flapping their wings in strengthen them.
The Audubon report found that there was quite a bit of variability in active nests at rookeries from year to year and it was not uncommon for entire rookery sites to be abandoned only to be repopulated again later. Leibezeit says that all indications are that heron populations are stable in the metro area.
"It's so beautiful there, down by the river at Maddax Woods," says Gaadenstroom. "Even if you aren't there for the herons you see eagles, flycatchers, sea lions, beavers. It's crazy to just sit and watch — eventually you'll see something amazing. It's still remarkable to me how many people who live here have no idea this is in their backyard."