Ravens in the City

by Doug O’Harra

Anchorage ravens begin their commute at dawn. As an orange glow backlights the Chugach Mountain skyline, the black birds rise into air liquid with cold. They cruise toward the glittering city in straight lines, as single-minded as wage slaves late for work. At least a thousand birds move at once, as furtive and quiet as large bats, following the creek drainages into town. Call it corvid rush hour.

By full sunrise, they have dispersed, flapping up the boulevards, drifting down the parkways, searching for the gooey jetsam of modern human life. By true daylight, the ravens are claiming perches throughout town – on light poles overlooking fast-food joints, snow berms beside grocery stores, dumpsters of all sizes and contents. The party lasts all day.

They concentrate on the big shopping malls and commercial strips, places an Anchorage biologist calls the “raven vortexes.” The birds love Chinese or Thai take-out, and rib joints, and any place that serves (then later discards) chicken. They’re suckers for French fries and snack food and stale bits of bread. They recognize the meaning of garbage bags. They congregate by the hundreds at the midtown solid waste transfer station and the city dump outside Eagle River.

In all, they coexist with Anchorage’s human society with uncanny grace, as though comprehending how to negotiate urban danger in a quest for urban food. They descend effortlessly through an anti-bird net at the Hiland landfill that readily snags eagles and frightens gulls. They strut through parking lots, shrewdly prancing a few hops ahead of moving cars or pedestrians. Let someone put out food – at the Eagle River fire station, for instance – and, after a few days, the black birds arrive en masse, as though communicating with each other through cell phones.

And then, at the end of each day, the ravens leave town. As the sinking sun casts long blue shadows, the birds gather in trees and snow berms. Dozens play the steam driven thermals above the municipal power plant at the corner of Glenn Highway and Muldoon Road. Sometimes scores of the birds soar and dive a couple thousand feet up in airborne maneuvers that grow wilder as dusk approaches.

Finally, they fly off – heading back into the mountains on the same flyways they took that morning. By the time alpenglow illuminates the Chugach in red hues, the ravens have pretty much disappeared for the night. Where do they go?
No one knew.

So Alaska state biologist Rick Sinnott, the guy who manages large wild animals inside the city of Anchorage, decided to find out.

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At the beginning, Sinnott figured the solution to Anchorage’s great raven mystery could be spectacular. Perhaps a remote ravine in the Chugach Mountains, with a thousand black corvids huddled on cliff faces. Or a secret valley of snow-shrouded spruce at the headwaters of Ship or Bird creeks, a place unsullied by human footfalls in winter. An enclave as fabulous and inaccessible as a wolf pack’s den.

“One of my favorite hypotheses was that there had some big raven roost somewhere in the mountains,” Sinnott said. “There would be a place where there were several thousand of them. …That was my main goal – to find where they’re going to roost.”

Like other species of gregarious and intelligent corvids – crows, jays and magpies – ravens were known capable of forming nocturnal roosts. Crows gather in a famous congregation of eight million in Oklahoma. In Maine, researchers found that ravens even used the roosts as a way of finding food in the forest – hungry birds spend the night with their well-fed brethren, then follow them to breakfast.

In Fairbanks, a huge roost of an estimated 800 ravens formed in a black spruce area near a cattle feed yard over several years, according to federal biologist Rod King. Another common roost is north of Fairbanks and often has 400 to 500 birds in it at night.

But no one had ever found such a place near Anchorage. Which didn’t make sense. As the largest city surrounded by untouched raven habitat, Anchorage in winter probably hosts more ravens than any other city on earth.

“It’s just a shining beacon for ravens,” says Idaho biologist John Marzluff, one of the country’s leading raven experts. “It’s a very common thing across the western U.S. for ravens to increase dramatically (in winter) and go into urban settings. But I think Anchorage is like the pinnacle.”

There were other mysteries as well. Where did Anchorage ravens go in the summer, for instance? Local conventional wisdom stipulated that ravens left town, leaving the pickings to gulls, geese and ducks.

And did they all go to the same delicious garbage pile every day? Or did the birds dumpster hop, moving from food source to food source, as flighty and urbane as yuppies doing lunch?

The answer was to track them down.

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Across the world, several species of large crow-like birds take the name of “raven.” But the boldest and smartest may the common raven, Corvus corvid, ranging across the Northern Hemisphere, from Europe to the Russian Arctic to the American continent.

Some scientists rate it the largest of all songbirds, with a length up to 26 inches. It’s a distinctive creature, with gleaming satin plumage that often has a purplish tint. It has a wedge-shaped tail, expressive fluff on its head, and intelligent eyes that surpass humans in their acuity. Its short wings are designed for long-distance travel, and it has one of the widest range of calls of any bird.

“It’s highly glossed plumage shows iridescent greens, blues, and purples, shining like a black dewdrop in the light,” wrote Bernd Heinrich in “Ravens in Winter. “And it dives and rolls like a black thunderbolt out of the sky or speeds along with liquid, gliding strokes. The raven is the paragon of the air, and more. It is assumed to be the brains of the bird world, so its deep, sonorous, penetrating voice demands immediate attention and respect, even though we have little or no idea what it says. It has a greater variety of calls than perhaps any other animal in the world except human beings. It is an imposing bird.”

Ravens have long figured in folklore and legend across the Northern Hemisphere. Because ravens would scavenge a human corpse as readily as any dead animal, many Europeans associated them with death and considered them evil. Even in the lower 48, especially on the East Coast, ravens were often poisoned or shot. Scientists say hundreds of thousands of ravens have been killed since the 1800s in North America and Europe.

But many northern peoples revered the birds. In Norse mythology, two ravens named “Thought” and “Memory” flew over the entire world each day, then at night whispered what they saw to Odin, ruler of the gods. In Alaska Native myths and stories, the raven was often the creator of the universe and benefactor – as well as trickster – to its human progeny.

When not prejudiced by old beliefs, people often take to ravens more than other birds. Certainly in Western American and Canadian cities, ravens are tolerated, if not admired, biologists say. In Alaska, that tolerance goes further, to the point where people welcome their presence.

“Because humans are inquisitive scavengers and hunters, we kind of identify with other creatures that do the same thing,” Sinnott adds. “Any animal that reflects our image – our sense of playfulness and curiosity – we find attractive.”
Idaho raven expert John Marzluff says years of no harassment has made Anchorage ravens seem bolder, even comfortable around people. “They certainly are more fearful here (in Idaho) than up there. They haven’t been adversely conditioned (in Alaska) to humans.”

At any given winter day, ravens haunt parking lots throughout the city like a squadron of spirits. They perch on light poles and call to each other. They drop off buildings with wings spread, gliding down in a parabolic sweep curves toward the ground and then they begin to flap and rise to the building scarp just across the street. Mated pairs follow each other, chasing off the unmated and less dominant birds.

Watch them, and you’ll see them everywhere – prancing along sidewalks, walking behind cars, landing on pickup trucks, hopping along snow berms.

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With a $69,000 grant from the military at Fort Richardson, Sinnott launched the first-ever tracking study of Anchorage ravens in the mid 1990s. It wasn’t going to be easy to catch enough ravens.

Sinnott consulted raven experts from Maine, where Marzluff and biologist Bernd Heinrich had worked out reliable ploys for capturing the savvy black birds.

Marzluff even came to Anchorage and helped Sinnott build a chicken-wire and wood trap near the Hiland Road dump on military land. The structure – 40 feet long, 20 feet wide and eight feet high – had a drop door triggered by a string.

For three months, Sinnott kept the trap baited with hunks of putrefying moose, skinned beavers, fish and chickens. He built a blind to hide in. It was all set.

Studies by Heinrich and others have shown ravens to be exceedingly cautious when investigating carcasses or food sources. They often take hours or days before actually feeding on a dead animal. Ravens test the food repeatedly – pecking it then flying off, apparently to see if it moves. The larger the chunk of food, the more cautious the approach.

Yet, despite this natural wariness, Maine ravens would have ultimately entered the trap, scientists say. At some point, the device would have captured dozens of birds in one fell swoop.

But Anchorage ravens never behaved like Maine ravens. They would land in branches, study the trap for a while, and then fly away. They would prance on the ground near the entrance. Then fly away.

“Our ravens would stand there and look at it,” Sinnott says. “They could wait an infinite amount of time.”

Only once did the trap work like it was supposed to – one hapless bird flew into it and was caught. On another occasion, a frustrated Sinnott burst from cover and flushed five startled birds into it.

“Judging by tracks and other observations, ravens seldom entered the trap,” Sinnott concluded.

So Sinnott tried a more predatory strategy, what he called “drive-by shootings.” Using a white state Fish and Game van, he’d drive close to ravens strutting in parking lots or near dumpsters. The birds, wary of people afoot, were often unconcerned about a moving vehicle.

From the open door, he’d hoist a “Net gun” launched a 12-foot net weighted with steel cylinders at the corners. That method caught 23. But Sinnott noticed that after he’d used the technique once, especially if successful, any observing raven flew away and never came back.

“After that, if they’d see the van coming, they’d take off,” he said.

Using padded leghold traps was more successful, nailing 26 of the birds. Sinnott would set the traps in snow banks, then scatter bait on the ground. Cheetos – an orange, crunchy cheese-flavored snack – at first proved irresistible to the ravens.

But, like drive-by shootings, the allure of Cheetos went stale.

Any ravens that observed a Cheetos-aided capture quickly learned to avoid Cheetos like they were pellets of poison.

On a second or third attempt, Sinnott would scatter Cheetos on the snow near the trap, hide in the van, then watch. The ravens would perch on light poles or snow banks, and study the Cheetos. Sometimes, he said, they’d look from the Cheetos to the state van, and back.

If other birds flew over, they would circle the Cheetos, appear to notice that nearby ravens were ignoring the food. Then they would leave too.

“It didn’t take very long before you had this little coterie of ravens that had seen it happen,” he said. “And the fact that one raven was suspicious, maybe was a big thing that immediately raised red flags for the others.”

In all, between fall of 1994 and spring 1995, Sinnott caught 62 birds, outfitting them all with leg bands. Some 54 birds received four-ounce radio backpacks with two-year batteries. No adult ravens were injured during the capture itself. However, a nestling died after it was startled out of a nest, and another bird died as it was handled – it apparently inhaled regurgitated fluids as it struggled.

Only seven of the 58 appeared to be juvenile birds, indicated by a brown tinge on their wings. Only 12 – about 21 percent – were dominant birds with mates, indicated by the black lining of their mouths caused by a hormonal change. (Non-dominant ravens have pink mouths.)

Sinnott, with the help of several fish and game technicians, began to follow the birds.

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The radio transmitters would broadcast every couple of days. Intermittent tracking proceeded that spring, into the summer, and on into the winter of 1996.

A typical winter tracking episode involved driving around Anchorage shopping malls and out to the dump with the receiver antenna mounted on the hood of the van. When the biologists picked up a signal, they would try to catch sight of the bird. Then they’d record it.

After hundreds of hours and in the air, including several thousand miles of driving on Anchorage streets, the scientists concluded that Anchorage raven society centered around a couple dozen “vortexes” – the Dimond Boulevard-Old Seward interchange by the state’s largest shopping mall, a three-mile-long commercial strip between two one-way boulevards, a solid waste transfer station and the city’s main dump, plus a few other shopping centers.

Most of the birds were found in the same locations, day after day after day. Yet a significant minority of birds habitually moved around, showing up one day the municipal landfill, the next at a Tudor Road rib joint restaurant, the next in the air, beating an inscrutable retreat toward Palmer.

Whether it was a dumpster outside a restaurant or a pile of garbage left by well-meaning humans, any reliable food source produced a spectacular following among the ravens.

“I think the thing that kind of strikes you is the variety of feeding opportunities for them – they’re really seem to know when the guys throw out the food,” said Marzluff, who spent a short time observing ravens in Anchorage. “They hit the Chinese restaurants when they dump out food. Then they go to the grocery store. They really have a sweet deal.”

Ironically, given that the military was largely paying for the study, few ravens appeared to remain on Elmendorf Air Force Base or Fort Richardson.

“I suspect this is because each installation has only one fast food restaurant,” Sinnott wrote, “and dumpsters and trash barrels are typically closed or emptied frequently.”

Sinnott at first thought the Anchorage population had to exceed 1,000 birds. Christmas bird counts by the Audubon Society had ranged widely over the past decade, from 400 to 600 to more than 1,500. As his study progressed, Sinnott gradually revised his estimate upward. He now thinks there may be as many as 2,000 ravens in Anchorage in winter.

In the summers, Sinnott hit another surprise. As he flew in his airplane, searching for the telltale beeping of the transmitters, the common belief that Anchorage ravens scatter for the woods collapsed. The ravens hadn’t left town after all.

“I thought if they left town, the would go to the mountains, in the wilderness,” he said. “But we found none – they were all in Anchorage or the Mat-Su Valley.”

The birds were hanging out in the same locations they preferred in winter: grocery parking lots, dog lots, dump sites. Most of the birds hadn’t moved far at all. “There are an amazing number of them nesting here in the summer,” he said.

Yet, as with winter travel, there were a few significant exceptions. Five birds that spent the first winter in Anchorage were later sighted scores to hundreds of miles away, in Skwentna, Fairbanks, Galena and Tok.

One bird that spent years nesting on Elmendorf Air Force Base, never straying more than half mile from its home territory near Muldoon and the Glenn Highway freeway intersection, took a trip.

“All of a sudden, he picked up and left,” Sinnott said. “We found him (100 miles to the northwest) in Chickaloon. It was just like a vacation out of town. And he wasn’t out there more than a couple weeks.”

After its adventure, the bird returned to its regular haunts in town. Sinnott never figured out what, exactly, the raven was doing there.

By winter of 1995-96, only about 20 ravens of the original 58 could be picked up on radio transmitters. Sinnott and technicians tracked them every couple of days. As spring turned to summer, and then to winter, more of the transmitters fell silent. Sinnott banded a few more birds last spring.

“Part of them are dispersing around the state,” he said. “What happened to the others is anybody’s guess.”

But what about the roost?

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Sinnott once caught sight of two ravens perched near each other in spruce near Point Woronzof a few hundred feet from the end of the runway at the international airport. As Sinnott studied them through binoculars, one of the birds suddenly flipped upside down while gripping the branch with its claws.

“He hung there like a bat,” Sinnott said.

The other raven watched closely. The upside-down raven held the pose for about 20 seconds. Sinnott could not believe his eyes. He thinks he must have blinked, because the bird suddenly righted itself on the perch.

“I still don’t know how he righted himself,” Sinnott said. “But I do know he was showing off. There were other birds there, watching.”

Biologists believe that such bold, risk-taking behavior is widespread among ravens, and isn’t just empty bravado. Flying wildly, flipping upside down, heckling a dog or prancing at a carcass often serve as effective strategies that attract potential mates.

“If you’re a scavenger or a hunter, being bold is an advantage,” Sinnott said.
In Anchorage, raven boldness shows up in quirky ways. Ravens were ripping out the weather stripping from windows in the new state court house. They steal windshield wiper blades, remove loose material from the beds of pickup trucks.

Add that to all the fabulous aerial maneuvers performed by ravens in the skies over Anchorage, and you’ve got one of the world’s premier avian performers.

“The one who has the best crown, the best strut, the best aerobatics is the one who’s going to attract a mate,” said Fairbanks biologist Rod King. “It stands to reason the raven who can do the inside rolls will attract the most attention from females. It’s definitely courting behavior.”

After pairing up, the dominant raven couples then stake territories around their nests, and chase off any lone birds that try to feed in their territory.

Which creates a problem for all those single, retiring birds that lack the right stuff. How do they eat in winter?

That’s where the roost comes in.

Researcher Bernd Heinrich, a sociobiologist from the University of Vermont, spent years studying the behavior of ravens in their roosts in rural Maine. In his book, “Ravens in Winter,” Heinrich described how ravens would study a carcass, sometimes visiting it off and on for days, yet not touch it. Then one morning, 20 or 30 birds would arrive all at once.

In Maine, food sources are almost always dead carcasses of wild animals. Heinrich and Idaho biologist John Marzluff experimented by dumping dead animals in certain locations, then observing what happened.

“The work we’ve done on exchange of information at roosts is really pretty fascinating,” Marzluff said. “We don’t know the mechanism all that well. … My guess is it’s a combination of vocal and a flight style. It may be as simple as – if you know where the food is, when it’s morning, you fly off and the others follow.”

After hundreds of episodes where non-dominant ravens appeared to share food, Heinrich concluded that the birds were acting more from shrewd self-interest than from any sense of human-like charity.

By congregating in a large group at a carcass, the single birds would chase off or intimidate the dominant pairs. Without that big group to overpower the territory owners, the single ravens wouldn’t be able to feed, Marzluff said.

“Almost all of the hundreds of carcasses that we have provided in Maine over the last 11 years were ultimately shared by crowds of ravens,” wrote Heinrich and Marzluff in a scientific paper. “Ravens share because their system serves the common good.”

But such a roost system might not be necessary in a place like Anchorage.

“It’s not going to work as well in the city, unless all of a sudden a dumpster becomes really really good and it last for a day,” said Marzluff. “They’re probably more keyed into these kind of always-available and lower-quality foods, like garbage.”

“Anchorage is a real strange situation, much different than what you have down south,” Sinnott added.

“Our birds are looking for dead animals too – road kills and moose that have starved to death. But they’re also looking for garbage.”

In the end, Sinnott never did find one mammoth roost. But he found a few smaller ones in surprising places. At least 80 black birds nestled in the superstructure and crossbeams of the A Street bridge over the Ship Creek basin at the Port of Anchorage, the city’s industrial section with semi-trucks rumbling past the sorting yard for Alaska Railroad freight trains. Small congregations formed in the hills on the U.S. Army’s Fort Richardson outside the landfill.

One flight over Anchorage revealed a signal over section of Campbell Creek outside the western edge of Bicentennial Park. Sinnott tried walking there in night, got within a few yards of a tree that seemed to have ravens in it. During the day, he returned, discovering thousands of raven tracks on the snow surrounding open holes in the creek, the ground littered with raven fuzz. Scores of birds had been roosting there, but they had moved on.

After several discoveries like this, Sinnott concluded that Anchorage’s raven roosts were spread around town, in unseen and unremarkable nooks. The city’s 2,000 ravens seemed to know that they can find food every day, scattered in so many locations and in such quantities, that there was no necessity in numbers, no advantage to be gained against mated pairs by the unmated masses. The location of breakfast wasn’t some secret to be guarded but a regular feature of the urban world.

“They can come back to the same dumpster every day,” Sinnott concluded. “I suspect they know the time when each restaurant dumps its chicken wings.”

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Toward the end of his study, on a clear cold night in March, Sinnott flew over the Chugach Mountains. The conditions were calm, the moon full. Ideal to find the last ravens still broadcasting.

Sinnott cruised over the Anchorage bowl and Fort Richardson, up Eagle River Valley, over the south fork to Crow Pass and Girdwood, with excursions along the major watersheds.

As the plane reached the headwaters of Ship Creek, near an unnamed pass overlooking a tarn called Grizzly Lake, a single signal blared from the receiver. As the plane passed over the ridge, the signal died. Sinnott circled again, picking up the signal off a sheer cliff face near the top of an unnamed peak.

It was the radio frequency of one of the most cosmopolitan birds in the study. Over the past year, Sinnott and his helpers had picked up the bird dozens of times all over town.

“You’d never know where he was going to be,” Sinnott said. “Sometimes he’d fly to the Eagle River grocery store or he’d come down Chester Creek. He’d kind of show up all around Anchorage.”

And here the bird was – 20 miles out, on a cliff in a part of the Chugach virtually inaccessible to anything except a mountaineering expedition.

Could that have been that the ultimate roost, a sheer face near the headwaters of Bird and Ship creeks, a 30-minute commute as the raven flies? Anchorage’s wily black birds are keeping the answer to themselves.

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