Archive for the ‘Urban influence on wildlife’ Category

North Spotted Owl (Credit: Wikipedia)

North Spotted Owl (Credit: Wikipedia)

Northern spotted owls have had a tough time of it in recent decades. Just when one threat to the species begins to decline, it seems, another is right there to take its place.

In 1990 the northern spotted owl was listed as threatened under the Endangered Species Act. This spurred a long and heated controversy between loggers in the area, who had built a booming industry around the region’s old growth forest, and conservationists, who viewed the owl as an “indicator species.” The divide grew when, in 1994, Clinton signed the Northwest Forest Plan, which was designed to protect northern spotted owls and other species that depend on old growth forest. Although the plan permitted logging at a sustainable level, its implementation slashed logging on national forest by 90 percent.

While the debate has settled as the northwest slowly rebounded from the loss of its timber industry, the northern spotted owl population remains threatened, and is in fact declining. New threats to the species have prevented the owl from rebounding. Climate change has led to further loss of habitat; winters and hot summers have contributed to a rise in insect outbreaks, fires, and disease in the old growth forests. The other main threat to the northern spotted owl: the barred owl.

Originally located in eastern forests across the US and Canada, barred owls have been making their way west, and now overlap all of the northern spotted owl’s range. The barred owl is larger and more resilient than the northern spotted owl, and is increasing competition in the northern spotted owl’s already scarce habitat. As pressures from a shrinking habitat and aggressive competing species increase, northern spotted owl populations continue to decline, as much as 7.4 percent per year.

Barred Owl (Credit: Wikipedia)

Barred Owl (Credit: Wikipedia)

Wildlife officials with the US Fish and Wildlife Department have developed a four-year experimental plan to kill barred owls in select areas of northern spotted owl range. The purpose of this experiment is to see if northern spotted owls rebound in areas where barred owls are less—or no longer—prevalent. Each area will be split in half. One half of each area will serve as a control area, where no barred owls will be killed. The other half will permit barred owl killing. These test areas will occur mainly on tribal and federal land, and will be located in northern California; in the Cascade range near Cle Elum, Washington; within the Oregon Coast range; and in the Klamath Mountains. The test areas will encompass 1,207 square miles, equaling about 0.05 percent of the northern spotted owl’s habitat.

Officials are not yet sure whether government or publicly contracted hunters will be tasked with hunting the barred owls, or how the killing will occur and what regulations will be set. Any hunting of the owls will require a special permit under the Migratory Bird Act, since barred owls are considered a nongame species.

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This experiment brings up several ethical dilemmas. Some opponent’s of the plan believe that officials are intervening in a natural process. If the barred owl naturally made its way into northern spotted owl habitat, the effects of that should, critics argue, be left to nature to sort out.  However, according to the FWS, it’s likely that  “the barred owl’s westward movement was caused by changes to the environment in the Great Plains as people increasingly settled there and dramatically altered the landscape.” So, how ‘natural’ is the barred owl’s presence in northern spotted owl range?

Further, we have to ask: would the northern spotted owl be better prepared for the barred owl’s invasion if the northern spotted owl population hadn’t declined due to logging? Or, if there was more available habitat, would the two species be able to co-exist in such a way that barred owls wouldn’t threaten northern spotted owls?

We are left with another pressing question: What is the ultimate cause of of this issue? Is the barred owl invasion an ultimate cause of the northern spotted owl’s decline? Or is the barred owl’s effect on northern spotted owl populations the result of the ultimate cause: habitat loss? Furthermore, if barred owls are an indirect cause to the decline in northern spotted owl, how would killing them be an effective long-term management strategy for preserving the northern spotted owl?

Of the proposed experiment, the FWS says:

“The U.S. Fish and Wildlife Service has identified competition from barred owls as one of two main threats to the northern spotted owl’s continued survival (habitat loss is the other). We are currently proposing an experiment to test the effects of removing barred owls from certain areas of spotted owl habitat to see if it would benefit spotted owls.  Removal of some members of a common species to protect or recover a rare species, while not unheard of, is not a typical management practice, and it is one we propose only in the most serious conservation situations.”

It looks like this experiment is putting the cart before the horse. I didn’t see any FWS studies examining the potential for northern spotted owls to naturally rebound if barred owls are eliminated from their habitat. Will population numbers still suffer as forest fires, fragmentation, and disease continue to reduce habitat? Is the naturally-occurring presence of barred owls a sign that nature is letting the northern spotted owl run its course? Or, conversely, if barred owls were pushed westward by human population growth, are we ethically responsible for managing the effects of their migration into northwest old growth forests?

Of course, I don’t have answers to these questions. I am only compelled to ask them. Wildlife and environmental management is rife with ethical debates such as this one, and the ways in which we protect and preserve nature will continue to require modification as the human population expands. Knowing when—and how—to intervene, or when to step aside, will only become more challenging.


Wildlife Officials Move Ahead With Killing Barred Owls

AP Newsbreak: Feds to start shooting barred owls

Northern Spotted Owl Recovery Information Site: Barred Owl Threat


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Most people are used to seeing some wildlife around town, but urbanites might start seeing a new critter in their backyards. According to a study highlighted at the October 5th EcoSummit in Columbus, Ohio, coyotes are becoming increasingly common in urban areas. The study, led by Stanley Gehrt of Ohio State University, pointed to a small coyote population living just 5 miles from Chicago O’Hare International airport as one example of the species’ increased prevalence inside city limits. The coyotes have inhabited a 1/3 square-mile range for the last six years, and seem to be not just living, but thriving.

There are several reasons coyotes easily adapt to urban areas, says Gehrt. A lack of common diseases has increased pup survival rates–they are five times more likely to survive in cities than in the wild. “None of the diseases they’re exposed to really impact them at all,” Gehrt said. Instead, cars have taken over as the leading cause of death. Food and water are also far more accessible in cities than in the wild, making it possible for coyotes to survive within much smaller ranges than they require in wild areas. But the ease with which coyotes adapt to city life might encourage an increase in other, larger carnivores entering urban areas. As coyotes become more common in cities, they may make it easier for mountain lions, wolves, and bears to enter and thrive in city limits.


Sitting at the edge of the Rocky Mountains, Boulder is already home to an abundance of coyotes, among other wildlife species. But even here, where coyote warning signs are posted on most open space trails and coyote sightings are common, if not expected, the migration of larger predators into the city has been an issue. This year alone, several mountain lions have made their way into Boulder–one was even found in an apartment pool area nearly two miles from the nearest open space. Bears, too, are making themselves more comfortable in Boulder’s streets. Neighborhoods skirting Boulder Open Space are familiar with bears–tipped over trash cans and scat in alleys are daily occurrences, but recently bear sightings have been reported further into the city, and sightings are becoming increasingly common.

Admittedly, I’m still fairly new to this area. Maybe the urban presence of mountain lions and bears isn’t abnormal at all; it’s just more than what I’m used to. Or perhaps the increase in wildlife within city limits is the result of our especially bad fire season–maybe, as small mammals and herbivores have come into the city searching for vegetation,  the animals that prey on them followed suit.  But it seems like Boulder, being one step ahead of other urban areas’ coyote populations,  is setting an example to support Gehrt’s theories about coyote communities leading to increased predator presence in cities.


CNN News Blog

Watch Out Urbanites, Here Come the Carnivores

OSU Research News

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