How well do birds tolerate people?


Turkey Vulture. Photo by Mark Gorges.

By Barb Gorges

Also published here:

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 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.


Turkey Vulture. Photo by Mark Gorges.

Bird of the Week: Peregrine Falcon

Peregrine Falcon

Peregrine Falcon. Photo by Pete Arnold.

Taken to the edge of extinction in North America because of pesticide poisoning after World War II, a ban on DDT and restoration work took the peregrine off the Endangered Species List in 1999. This cliff nester feels at home in urban landscapes where it has been reintroduced. It is seen occasionally at Cheyenne’s city limits as it migrates through here in spring and fall, preying on ducks and other waterbirds at high speed.

Published Sept. 9, 2009, in the Wyoming Tribune Eagle. Text by Barb Gorges, photo by Pete Arnold.

Peregrines come back with help from friends

Peregrine Falcon

Without captive breeding techniques honed by centuries of falconers, the population of Peregrine Falcons may not have recovered. Photo courtesy U.S. Fish and Wildlife Service.

Published May 13, 2012, in the Wyoming Tribune Eagle, “Peregrines back with a little help from friends.”

2014 Update: eBird shows several peregrine observations in the area around Cheyenne, but nothing more recent than 2010.

By Barb Gorges

Peregrine falcons were listed as endangered in the U.S. two years before I opened my first bird field guide in 1972.

The guide, “The Birds of North America,” published by Golden Press in 1966, did not allude to the peregrine’s diminishing population. It only said it was “a rare local falcon.”

However, in the era of an awakening environmental consciousness, we all heard about the peregrine, a very handsome poster child for the drive to ban DDT, one of the pesticides responsible for poisoning birds of prey and causing their eggshells to be too thin for un-hatched young to survive.

One doesn’t expect to meet an endangered species in the wild, especially when ornithologists had declared it extirpated in the eastern U.S. by 1970 and in trouble in other parts of the world (peregrines are found everywhere except the Sahara, the Amazon and Antarctica). But I had another encounter with a peregrine last month, just outside Cheyenne.

My six peregrine observations, all since 2003, have been around Cheyenne, at either Wyoming Hereford Ranch or Lions Park. All but one were in spring.

I remember the first sightings, on Audubon field trips, for which I was relying on more experienced birders for identification. Once, at WHR Reservoir No. 1, we saw a peregrine in one of those legendary dives–once clocked by a scientist at 200 miles per hour.

It slammed into an unsuspecting duck standing on a sandbar. The peregrine’s former common name was “duck hawk”–ducks being a favorite among the many kinds of birds they eat.

Last month, my husband Mark and I saw a bird sitting in a cottonwood below the same reservoir, watching us. It had all the peregrine field marks, including the dark cheek patches, which must have been the inspiration for those cheek pieces for first-century Roman centurions’ helmets.

Peregrines have been favorites of falconers for 3,000 years. While the young can be taken from wild nests, they are also bred in captivity. In 1970, the founder of The Peregrine Fund, Tom Cade, began breeding them in earnest, as did Bill Burnham of Fort Collins, future president of TPF, beginning in 1974.

By 1984, TPF had opened the World Center for Birds of Prey in Boise, Idaho. By 1997, 4,000 peregrines had been bred and released into the wild. By 1999, the peregrine was off the Endangered Species list. The fund continues to work to conserve raptor species around the world.

It isn’t quite the same as the old days for the peregrines. Someone thought of also introducing–or hacking–them into cities that have plentiful pigeon prey and tall buildings that would imitate their cliff-face nesting habitat. Urbanites could be seeing peregrines much more often than we do.

While peregrines went missing in the eastern U.S., what happened to them in Wyoming? I asked Bob Dorn, co-author with his wife, Jane Dorn, of the book, “Wyoming Birds.” From his research, he was able to give me a list of over a dozen observation dates back to 1929.

In 1939, Bob said O. C. McCreary categorized the peregrine as “a rather rare summer resident,” usually indicating that they are breeding, and “an uncommon migrant,” meaning not quite so rare during migration. As Bob put it, “When you’re at the top of the food chain, you are in scarce numbers.” (Somehow, that isn’t true of humans.)

The Wyoming Game and Fish Department’s species account states that by 1970 Wyoming had no viable breeding population. They formed a partnership with TPF and over 15 years, 1980-1995, introduced 384 captive-bred peregrines. It was successful. There were 90 breeding pairs recorded in 2009, the most recent information available.

Today, breeding peregrines tend to be found in the northwest part of the state. Down here in the southeast, we have the potential to see migrants from April through May.

The most recently published field guide I have, “Peterson Field Guide to Birds of North America” (2009), does mention the peregrine was endangered—small concession to the idea that the hobby of bird identification can no longer be divorced from bird conservation.

The new “Peterson” range map shows there is still a big empty area in the middle of the country where the “Golden” guide had indicated wintering peregrines nearly 50 years before. But it also shows summer range, presumably breeding range, where the “Golden” guide did not.

Unfortunately, many threatened or endangered birds are not as charismatic as the peregrine. Experience with captive breeding may be nonexistent and the reason for a species’ plummeting population may not be as simple as a particular pesticide. The commonality however, is that human experiments with new technology often produce unexpected, bad consequences for some birds, while accidently promoting the unwanted reproduction of others–think starlings.

Meanwhile, birders continue to collect and share observations, causing range maps to continually be redrawn. Mark’s and my single peregrine sighting on April 8 becomes part of the larger story.

Keep your eyes open, too.