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Meet the Cormorants of the Second Narrows Bridge

Pushed from their habitat, the largest colony in BC found a new home beneath commuter traffic.

Christopher Cheung 21 Feb 2024The Tyee

Christopher Cheung reports on urban issues for The Tyee. Follow him on X @bychrischeung.

The Ironworkers Memorial Second Narrows Crossing, stretching across the blue of the Burrard Inlet to connect Vancouver to the North Shore, is surrounded on all sides by industry.

Tracks, docks and warehouses line the shore. Asphalt and sulphur are pumped out from production plants. The Chevron terminal supplies gasoline, diesel and jet fuel from the nearby refinery. The air is filled with the rumble of trains and trucks, cars and cargo ships.

There are no cliffs here, no calm islets.

And yet, this bridge is where a bunch of birds have been coming to nest and rear chicks in record numbers — living on the beams of its underbelly is British Columbia’s largest colony of double-crested cormorants.

Commuters might be startled to learn that there are birds and nests in the hundreds beneath the bridge they cross daily. So might the locals who walk the parks on the inlet but aren’t close enough to notice the presence of such a colony under the bridge. And even if they spot a black bird, there’s no way they can make out the defining details of the cormorant: stocky bodies, long necks, webbed feet, hooked bills. Surely, it must be a crow!

The birds are under the bridge because of us.

Across North America, cormorants have been abandoning their natural nesting sites to avoid all the things that come with urbanization, from people to vehicles to noise. If human disturbance flushes a chick from its nest, they’re exposed to predators and sunlight, which can kill them within 11 minutes.

Seeking new places to nest, cormorants have been drawn to an unnatural habitat: bridges like the Ironworkers.

“This is actually an incredible thing, to have them living right under a bridge in a very urbanized setting,” said Ruth Joy, a statistical ecologist at Simon Fraser University who has been studying the state of the birds in the region.

Curiously, cormorants’ nests have been found to have anthropological influence. Natural components of nest construction are branches, feathers, grass, seaweed and rootlets, which are coated with guano, their droppings. But the birds also use human debris for their nests, like paper and plastic bags, plus more unusual finds like gloves, sunglasses and cigarette packs.

Birds on bridges have left governments with a challenge. What to do with public infrastructure that has become a significant habitat for a species on the decline?

Double-crested cormorants were almost driven to extinction by DDT, the insecticide that caused reproductive failure. But after it was banned by the United States in 1972, the population spiked. In B.C., however, they are considered an at-risk species.

Between 1984 and 2001, the province’s population dropped from about 1,600 pairs to 600 owing to human disturbance and predators like bald eagles.

That means the birds successfully nesting beneath the bridge are all the more important.

Joy and her students at SFU have been trying to get a closer look at the bridge colony. Equipped with tech like artificial intelligence and robotic camera mounts, they’re investigating what a shared future could look like with the displaced bird hoping for a home in our city.

The bird of the devil?

“They’re not everyone’s favourite bird,” said Samantha Broadley, a master of science student and part of the cormorant crew of researchers under Joy’s supervision. “They’re a bit odd-looking. They’re not as cute as a songbird. And there’s a huge negative connotation around them.”

Elsewhere in North America, cormorants have been treated with lethal force. They’re generally considered a pest because of their tendency to nest in large numbers, perceived effect on sport fisheries and the harms of their guano on vegetation.

Atlantic provinces permit kills while Alberta, Ontario and Quebec have undertaken large campaigns to shoot cormorants and oil their eggs to prevent hatching.

And going way, way back, God doesn’t like cormorants either.

The cormorant is mentioned in the Old Testament by Yahweh as an unclean bird. In the poet Dante Alighieri’s Divine Comedy, Satan’s wings are compared to a “cormorant so vast” like a “twilight bat.” John Milton later adopts this affiliation in Paradise Lost, with Satan sitting on the Tree of Life “like a Cormorant... devising death.”

Even if you’re not religiously inclined, the birds stink of fish.

But the idea of cormorants as pests shouldn’t cloud their important role.

“Biologically speaking, they’re an important high trophic level species,” said Broadley.

Cormorants, fish feeders, play a key role in the food chain, and they have a lot to teach us about the health of the marine environment on the province’s south coast.

“Seabirds are what we call an ‘indicator species,’” said Joy.

For example, the population trajectories of the southern resident killer whales and double-crested cormorants line up closely, a mystery that researchers like Joy haven’t yet solved.

“If you’re interested in what’s going on in the Strait of Georgia and your seabirds are not doing well, that’s an indicator that there’s something going on at a bigger scale.”

A double-crested cormorant with a turquoise eye and orange hooked beak looks over the water.
After the pelagic cormorants, double-crested cormorants settled on the Ironworkers Memorial bridge in 2010. Photo courtesy of Macus Ong.

New neighbours

When cormorants come to the city, it might feel as though they’re intruding into our territory. But it’s we humans who have been intruding into theirs. There were a number of incidents of human disturbance around the year 2000.

At Bare Point, a log boom displaced a colony.

On Passage and Gordon islands, it was new houses above their nesting grounds that bothered them enough for them to leave.

In Vancouver, bike traffic disrupted the birds. The city’s last natural nesting habitat for pelagic cormorants — a smaller, slimmer species than the double-crested — was the basalt cliffs between Prospect Point and Siwash Rock in Stanley Park. After new seawall bike lanes were installed, the population of pelagics dropped from 91 to 12 pairs in 2000, disappearing completely by 2014.

But the cormorants that took to the Ironworkers Memorial bridge proved much harder to get rid of.

Pelagics first started nesting there in the early 1980s, to the alarm of the provincial Transportation Ministry, which owned the bridge.

Early one April, the ministry removed 85 nests ahead of the egg-laying season. But by the end of the month, 70 had been re-established and contained clutches of eggs. The ministry removed them, too, but returned in May to find 80 new nests.

In 2009, the pelagics received new neighbours. A colony of double-cresteds moved onto a nearby transmission tower to nest, the first time that particular cormorant species had ever done so on a piece of infrastructure in the province.

In the next few years, the double-cresteds joined the pelagics on the bridge, eventually outnumbering them and becoming the dominant species on the bridge by 2016.

Researchers over the years took inflatable boats out onto the inlet to observe and count the birds. It was a cumbersome method, not to mention a risky one that could stress out adult birds and their chicks.

When Macus Ong joined Joy’s cormorant crew to research the birds as part of his master of science in ecological restoration, there was grant funding from the Canadian Wildlife Service for cormorant monitoring. There was an idea to go big and use the money to rent choppers.

“Helicopter rides aren’t cheap,” said Ong. It would have been a rare opportunity to allow him to monitor cormorants from more than one perspective. “But there’s also the issue of animal behaviour disturbances.”

Ong, a photographer, decided to experiment with technology that was invented for a very different purpose: to capture landscapes from the surface of the planet Mars.

Zooming into infinity

The GigaPan EPIC Pro series of robotic mounts are a coveted and a pricey tool for photographers obsessed with detail.

“People get a kick out of it because you can zoom into infinity and it’s so clear,” said Ong.

A man with a yellow jacket and red cap presses buttons on a camera mount attached to the top of a tripod. There is a camera on top of the mount. He is standing on the rocky shore by the foot of a bridge on a cloudy day.
Macus Ong programs a GigaPan mount with a Sony camera to capture a panorama of the bridge. Photo courtesy of Macus Ong.

GigaPan started off as the commercial spinoff of a collaboration between NASA and Carnegie Mellon University. The original technology was developed to help Mars rovers like Spirit and Opportunity document the landscapes of the red planet in the highest resolution possible.

From there, the company developed robotic mounts for other photographers to use.

“You program it, how many rows versus how many columns, and you just let it run,” said Ong. “It will start taking photos from the first tile all the way to the last tile. It covers 30 per cent overlap in each photo, important for it to be recognizable by the software so it can stitch everything together.”

Enthusiasts have used GigaPan to photograph Mount Everest, cityscapes and, on our own blue planet, night skies dotted with stars. It has also been popular in baseball stadiums. Media have taken panoramas of the entire audience on game day for fans to go in afterward to find themselves among the thousands.

It’s very Where’s Waldo? A group of Australian researchers borrowed the idea of capturing many humans and adapted it to the task of documenting many birds, using the GigaPan to photograph a colony on the remote Albatross Island.

It was proof that the GigaPan could be used for animal research, so Ong decided to spend some of the Canadian Wildlife Service grant funding on the robotic mounts for monitoring the cormorants.

Ong did not get permission from the Ministry of Transportation and Infrastructure to monitor the birds from the bridge itself, which meant that the best spots to observe the bridge were on private property on both shores. He had to gain permission from a guarded film set on the north side and a grain facility on the south, which required proposals, presentations and training before he was granted access.

With such tight security near the bridge, no wonder the public knows so little about the cormorants. Even the film workers who spent so much time on the inlet were surprised.

The screenshot of a program with a 20-by-13 grid of images, stitching them together.
Software at work stitching the many images captured with the GigaPan. Screenshot courtesy of Macus Ong.

Ong returned to the sites over the course of 10 months. He took more than 100 panoramas composed of thousands of images of the cormorants and their nests.

His cormorant census during the peak of the nesting season in 2020 found the bridge’s largest population of birds to date — 60-something nests of pelagics and 296 nests of double-cresteds.

Counting colonies with AI

Ong and Joy’s other students in recent years have monitored cormorant colonies in natural habitats elsewhere on the coast, such as the sea cliffs of Mitlenatch and Gabriola islands.

They set up GoPros, powered by solar panels, to capture time-lapse photography of the birds to see whether attempts to nest and raise young have been successful.

To help count birds and nests, they developed machine learning models — artificial intelligence.

“We fed and trained the machine with hundreds of images and hours,” said Ong.

It’s hard enough to count birds in the hundreds. Seabird colonies can have millions, making these models an important tool in the future of such research, expanding to other species and saving labour.

A screenshot of a photo of cormorants nesting under the beams of a bridge with an artificial intelligence identifying the birds and the nests using coloured boxes.
The machine model at work, counting cormorants in red boxes and nests in yellow. Screenshot courtesy of Ruth Joy.

On Mitlenatch Island in the northern Strait of Georgia, cormorants are always spotted on a clifftop during nesting season. As a result, what the GoPro cameras uncovered was shocking.

“Mitlenatch is a sink. Nobody knew there was zero nest success,” said Joy. “People have been counting cormorants in Mitlenatch Island since the 1950s assuming that there’s a healthy population — until we put the cameras to show that actually all their eggs are eaten and there’s no successful hatching of any young. So that was news to a lot of the volunteers that really love that island.”

In many of the images, bald eagles were spotted visibly sitting among the empty nests. Other photos showed gulls and crows as well, and volunteers noted that river otters and mink can also access their nests.

At the Gabriola site, the cormorants made nests on steeper cliffs with moderate success, but predators could still access them.

“The bald eagles can flush,” said Joy. “The crows and the gulls can just walk in and eat whatever eggs that are exposed.”

A GoPro with a solar panel mounted on the side of a cliff, watching cormorants.
The GoPro at work at sea cliffs on Gabriola Island. The exposed location means that predators have relatively easy access to the nests. Photo courtesy of Macus Ong.

The Ironworkers Memorial bridge, with the beams of its underbelly, happened to offer protection.

“What we think is happening on the bridge is that it’s a haven for cormorants because it’s hard to access in between the various structures,” said Joy.

“You have to have a certain athleticism to be able to land on the bridge. Cormorants are very good at flying, banking, then hitting and dead-pointing onto a small place like a small fissure in a vertical cliff or a bridge beam.” Bald eagles are too ungainly to grab hold of a perch with such precision.

The unnatural habitat has now become home to half of the province’s population of double-crested cormorants.

“We think it’s a really important source for the population to maintain its numbers,” she said. “The bridge has just been full of surprises.”

Bridging a relationship

Last summer, Samantha Broadley travelled down the coast to Astoria, Oregon, where she got to meet Cormie the double-crested cormorant, an ambassador for her species.

In Cormie’s region, some 30,000 of her kin living on an island in the Columbia River were blamed for eating endangered baby salmon. Various agencies and local tribes approved the U.S. Army Corps of Engineers to launch a kill program.

As the birds were being exterminated in the thousands, the survivors fled in 2016. Many settled on the nearby Astoria-Megler Bridge that spans the state border between Washington and Oregon, where they’ve multiplied and are expected to number 10,000 this summer. The Seattle Times called it “the cormorant disaster of the Columbia,” noting the irony of killing one native species to save another and evidence that the cull might not help salmon populations at all.

Cormie, caught in the middle of all this, was rescued by Astoria’s Wildlife Center of the North Coast after being plucked by a bald eagle as a nestling and dropped into a tree. She has sparkly turquoise eyes that turn aquamarine during breeding season, as the inside of her mouth turns cobalt blue. This is also when white tufts grow out on the sides of her head, from which double-cresteds get their name.

Cormie is a waddler on land and an expert diver in water, and she loves catching money.

Left image: a woman holding a camera with a telephoto lens is on a boat looking towards part of a bridge, which has many cormorants perched on a ledge. Right image: a cormorant shows off its wings on an artificial blue rock while a woman in her 20s smiles behind in admiration.
Left: student Samantha Broadley tours the Astoria-Megler Bridge by boat, home to thousands of cormorants. Right: Broadley visits with Cormie, the resident blue-crested cormorant rescued by the Wildlife Center of the North Coast. Photos courtesy of Ruth Joy.

“When you get to know them in the way that we have, looking at the time series of GoPros over the course of the summer every day, they’re just really silly and I think that’s reason in and of itself to protect them,” said Broadley.

“They really dote on their partners,” added Joy. “They don’t like their neighbours, but they love each other. So watching them preen one another and do some of their courtship rituals is very beautiful.”

Battles like the one taking place in the Columbia River region prompt the question of how to live with the birds in B.C. A freedom of information request to the province by an unknown party in 2022 unearthed 1,618 pages of extensive correspondences, contracts and reports on the challenge of managing the Ironworkers Memorial bridge’s cormorants in recent years.

The Ministry of Transportation and Infrastructure told The Tyee in a statement that it recognizes the significance of the bridge colony and the success of the fledgling young. The ministry also noted that its primary concern is the longevity of the bridge.

“Bird feces and nesting material can corrode the bridge’s structural steel by trapping in moisture and contaminants,” read the statement. “This deterioration’s effect and consequences accelerate over time, as once the protective coating fails, the corrosion affects the longevity of the structure. To manage this, staff undertake ongoing repair and drainage improvements in affected areas.”

No attempts to exclude cormorants have been installed on the Ironworkers Memorial bridge, according to the ministry, which is continuing to monitor the effects of nesting.

The ministry is reaching out to partners including the City of Vancouver to develop a more comprehensive plan to protect the bridge and manage the birds. Pelagic and double-crested cormorants have been nesting on the city’s Granville and Burrard Street bridges. When the city was doing seismic upgrades for the Granville Bridge a few years ago, netting was installed to keep the birds out. But before the netting was fully secured, multiple birds got caught and died.

The ministry also mentioned that it is considering alternative nesting platforms, something the California State Transportation Agency did with its San Francisco-Oakland Bay Bridge, nicknamed “cormorant condos.”

Joy and other researchers believe more evidence is needed on everything from the diet of cormorant colonies and the effect of their guano on infrastructure.

Ong has since graduated and passed the torch and tech to other students studying cormorants, but he’s gained a special appreciation for the birds after spending so much time observing them.

“You could equate them to crows or ravens just because they’re black, but in the right light at the right time of day, the colour is there: it’s green, it’s purple, it’s violet,” he said. “It’s fascinating to see birds that people perceive as just black looking so beautiful.”

Seeing how the cormorants have thrived on the bridge, he’s convinced we can live together.

“How do we build better for humans as well as wildlife?” he asked. “Everything is about coexistence, right?”  [Tyee]

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