t’s a been a great comeback for the Great Blue Heron in Beacon Hill Park.
Sixteen years after bald eagles decimated their eggs and chicks and forced them to abandon their established heronry in Beacon Hill Park, Great Blue Herons have returned to new trees farther inside the park near the bandshell.
Michael Creighton, supervisor of park operations and natural areas for the city of Victoria, said the last provincial survey in 2019 indicated there are 85 nests in the stands of Douglas fir and other trees there, and the population seems to be holding and possibly increasing, even as bald eagle attacks are starting again.
“There is certainly no indication they are down in numbers this year,” said Creighton.
The provincial survey showed 85 mating pairs with 1.2 chicks per nest, slightly below the provincial heronry average of 1.4 chicks.
The heronry, which had been established since the early 1980s at Avalon Way on the Douglas Street side of the park, had reached a peak of about 110 nests when the devastating eagle attacks occurred in 2007.
Most of the herons flew north to Cuthbert Holmes Park along the Colquitz River in Saanich, where they suffered similar attacks, but they did start trickling back to Beacon Hill in 2011.
By 2012, 54 nests were counted.
Creighton said the herons establishing new nesting sites in about 30 trees near the bandshell might have had something to do with keeping their enemies close.
Some researchers suggest that herons will deliberately build their nests near bald eagle nesting sites because eagles are territorial and the herons know it. So, the herons accept losing some of their brood to the eagles, knowing those same eagles will keep other eagles away.
“They had been moving year after year closer to the eagle’s nest,” said Creighton. “It might mean sacrificing a few [chicks] for the greater good of the colony.”
Creighton said bald eagle attacks have been happening this spring, likely because the eagle nest that was in a grand fir at Bridgeway and Chestnut Row near the current heronry is now gone.
It’s believed the nest was moved to the park’s southeast corner. That could be allowing other eagles a way in to the heronry.
He said at least two juvenile eagles have been preying on the heron nests this year as the heron chicks are in the four- to six-week stage.
When the attacks happen, usually early morning and evening, the whole group of herons rises up “like a giant umbrella and start circling, getting really vocal, but to no effect,” said Creighton. The eagles get little resistance.
It’s sad to see chicks being taken, he said, but added “it’s part of nature — it happens.”
Eagles will also grab eggs early in the spring and then come back for fledglings to feed their own chicks.
Creighton said there is no daily data collected on the populations of the heronry, so it’s impossible to tell how many eggs or chicks have been taken.
Eagle attacks on heron nests are also common this spring in Stanley Park, where nesting has been happening for over a century and for the past two decades near busy public tennis courts.
The same squawking and mass flight ritual is taking place there when eagles are attacking in the early evening.
Great Blue Herons usually prefer quiet spots away from people, but experts say they may be tempted by nearby shorelines in both parks for their main foods, small fish and crabs.
Maria Morlin, a Vancouver Community College biology instructor who lives near Stanley Park and produced a documentary about the park’s heronry, said the herons may choose areas because of the types of trees or because “it’s close to humans which may afford some protection from predators.”
That was certainly the case on a recent Friday as the herons seemed unfazed by the sounds of brass and woodwind instruments just below them as members of the Royal Canadian Navy’s Naden Band and their counterparts from the visiting Japanese navy played a free concert in the park in front of about 300 people.
A couple visiting from Colorado on their way to see the bands stopped to check out the busy heronry, as adults flew in and out of the trees and chicks were visible in the nests.
“It’s amazing and beautiful,” said Michelle Johnson.
“We have herons in Colorado but we’ve never seen this,” said her husband, Andy Johnson. “To have this right in the city is quite something.”
Creighton said there is concern about the heronry among park users, including tourists who come to the park just to view the herons. “People think we should intervene [to save them from eagles], but we have to let nature take its course.”
Adult herons stand at 135 centimetres, about the size of a Grade 3 student, but weigh only two or three kilograms, according to the Environment Ministry.
They lay three to five eggs in April or May and hatch in about 30 days. Within two months, the young birds are able to fly and can reach at least 23 years of age.
They can be quite vocal. The ministry said because their call sounds like they’re screaming “Frank,” the bird is known in some place as Old Frankie.
Populations of the Pacific Great Blue Heron are on the decline due to habitat disruptions and sensitivity to human activities. It’s on B.C.’s Blue List of vulnerable species, and the Committee on the Status of Endangered Wildlife in Canada has designated the Great Blue Heron as vulnerable.
Heron eggs, nests and the trees used for nesting are also protected under provincial law.
— With files from the Vancouver Sun
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