How well do birds tolerate people?

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Turkey Vulture. Photo by Mark Gorges.

By Barb Gorges

Also published here: https://www.wyomingnetworknews.com/do-birds-tolerate-people

Every soaring bird I saw in early February along 1300 miles of interstate highway between Nashville, Tennessee, and Fort Lauderdale, Florida, was a black vulture or turkey vulture.

However near Vero Beach, Florida, where we were visiting Cheyenne snowbirds Karen and Fred Pannell, there was a black bird of a different shape, a magnificent frigatebird, a life bird for both me and my husband Mark.

But about those vultures, were they really more abundant along the interstate than away from it? Were they waiting for roadkill? We passed a couple landfill “mountains” that were big vulture magnets too.

We think wild birds go about their lives oblivious to people, or at least avoiding us. Except for birds coming to feeders. Or ducks at the park looking for handouts. Or Canada geese that enjoy eating the grass on park lawns and the leftover grain in farmers’ fields.

We know that some human activities are detrimental to birds. But how many are beneficial to them? Chimney swifts have experienced both. We took down the old hollow trees they used to build their nests in and they moved into our chimneys.

The speaker at February’s Cheyenne – High Plains Audubon Society meeting, Cameron Nordell, relayed interesting research results on nesting ferruginous hawks and their reactions to people. Nordell, Raptor Fellow at the University of Wyoming Biodiversity Institute, is with the Wyoming Raptor Initiative.

In his previous work in southern Alberta, Nordell and his colleagues experimented in part to see at what distance hawks would flush from their nests as researchers approached by vehicle or on foot to check the nests for other aspects of the study.

Southern Alberta is a mix of agriculture, oil and gas and other development. The farmers and home owners have planted trees on the prairie and the ferruginous hawks have found them to be great for nesting—they are a ground-nesting hawk otherwise. The trees give them better protection from predators.

However, along with people came another species that climbs trees—and raids nests—racoons. Barns and other structures have helped increase the population of great horned owls and they too prey on the nestlings.

Ferruginous hawks nesting near the busiest roads were more tolerant than birds that had not seen as much traffic. Approaching vehicles were tolerated better than approaching people.

Raptors have been shown to hang out by roads, looking for injured prey species. The problem is that they risk getting hit by vehicles too.

The Wyoming Raptor Initiative (see https://wyomingbiodiversity.org/Initiatives-Programs) wants to understand the state’s raptors better, including the road problem. It has two goals:

“(1) To synthesize our scientific understanding of raptors in Wyoming so that the public, scientists, land managers and energy companies will be better informed in developing and implementing future conservation strategies and land mitigation efforts.

“(2) To foster appreciation of raptors in Wyoming and the world through education and outreach efforts.”

Nordell and his colleagues will be looking at previous studies of raptors in Wyoming, gathering more data, talking to all kinds of people to get more information, and then they’ll relay what they learn.

What will they discover about Wyoming’s ferruginous hawks, for instance? What human activities help them or harm them?

Nordell also studied arctic peregrine falcons near Hudson Bay, where there were few direct human impacts. However, the weather was ferocious. Too much rain, and a young bird, poorly nourished, could succumb to the cold rainwater collecting in the cliff-face nest. Better-fed youngsters had better survival rates.

The next questions: What affects the availability of peregrine prey species and the peregrine parents’ ability to bring food back to the nest? Is there any human influence on their success? Are humans linked in any way to that Arctic location getting demonstrably rainier?

What will be discovered about peregrines in Wyoming? I watched one nail a duck on a ranch reservoir just outside Cheyenne once. The human-made lake attracted the peregrine’s food target—southeastern Wyoming doesn’t have many natural water bodies.

I look forward to answers from the Wyoming Raptor Initiative. I’m sure they will also discover many more questions.

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Turkey Vulture. Photo by Mark Gorges.