Category Archives: population

More Bird Species Found When Willows Rebound

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A paper in the September issue of Ecological Applications says that when previously stunted willow trees near rivers in Yellowstone National Park started to grow, the diversity of songbird species found within the willow stands increased.

The study grouped the willow stands into three types: suppressed (likely by over-browsing and -grazing by elk and bison), released (where the willows had begun to grow), and previously tall. The “released” and “previously tall” willow stands had similar range in vegetation heights, but were not distributed over the landscape in the same way.

Because the diversity of songbird species in both the released and previously tall willow stands were similar, the researchers concluded the vertical complexity was more important to supporting that diversity than horizontal complexity.

The study has implication for other places where tree growth has been stunted by over-browsing by deer, moose, elk, or other animals.

The study does not address the reason why the willows started to grow (“…a possible consequence of wolf [Canis lupus] restoration, climate change, or other factors.”), so no help there. But if you need more data on the connection between tree height and songbird diversity, you can get it in this paper.

Abstract and access to the article through subscription or fee, here on the Ecological Applications site.

A free look at the paper on a researcher’s Web site, here.

Photo: Willow catkins in Yellowstone National Park, J. Schmidt, courtesy of National Park Service.

Climate Has Already Shifted Habitats

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A paper in the current issue of the journal Science says that the distribution of many plants and animals has shifted toward the poles or to higher elevations because of climate change. But what is really interesting is that the meta-analysis of other papers on changes in species distribution shows that plants and fish are moving north and up at the same rate as birds and insects. (There wasn’t much data from the southern hemisphere.)

That’s because species aren’t actually moving, the paper says. They are reproducing less at the hotter edges of their ranges and more at the cooler. They are moving at the rate of reproduction, not at the rate they can flee. Also, they found certain species within groups are moving much faster or slower than the group as a whole. So one species of butterfly may have shifted its distribution drastically, while another species has stayed put.

Media accounts are using the distribution of specific species, such as pika moving to higher elevations, to show the paper’s findings, but no specific species are mentioned (although a study of mammal distribution in Yosemite is mentioned in the supporting materials).

Read the paper in Science here (subscription or payment required).

Read the description of the work in Science Now here.

The journal Nature weighs in on its blog too.

Even if the predictions in the paper aren’t helpful for your work, the story is getting widespread coverage, and given the polarization in the US over climate change, there is sure to be a lot of chatter.

General media accounts:
USA Today 
New York Times blog
Toronto Star
Washington Post

Another Science paper on the implications of climate change has also been getting a lot of press, and we’ll take a look at that on Monday.

Photo: Ochotona princeps (pika) Location: Tokopah Falls, Sequoia National Park Date taken: 2003-06-13 Photographer: Justin Johnsen License: {{GFDL}})

20 Mountain Lions in Nebraska’s Pine Ridge

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A recent dog-tracking survey and DNA analysis shows that Nebraska’s Pine Ridge, in the panhandle, is home to 19 mountain lions. Scat-sniffing dogs found the scat, then 33 scat samples were sent for DNA analysis. The analysis revealed 19 individual mountain lions present in the region, which is near the border with South Dakota, and its known mountain lion population.

The story broke earlier this month. Here is a quick summary from Nebraska Central News. Another report comes from the Kearney Hub, which headlines with the biggest possible number of mountain lions. And here is a more in-depth report from the Lincoln Journal Star.

The Cicada Paradox

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Photo: Philip N. Cohen

As Brood XIX cicadas emerge in the South, you would think that local birds would be preparing for a once-every-13-years feast. But, rather than flocking in and chowing down, bird numbers decline in regions experiencing a periodical cicada emergence. These declines have been confirmed by the annual Breeding Bird Count (BBC) that takes place across the country in May and June.

Scientists at Cornell University’s Lab of Ornithology, the University of Maryland, and the U.S. Department of Agriculture wondered whether the loud trill of the cicadas was drowning out bird calls, so BBC surveyors merely didn’t hear birds that were still there; whether something about the cicada emergence drove birds away from an area; or if birds experienced a true population decline during cicada emergence years.

In a study published in the journal Ecology, they compared various measures of bird populations in years of cicada emergence, and years without a cicada emergence. They also looked at those population measures in places where the cicadas could be heard, and in places where cicadas couldn’t be heard.

If it was just a matter of the surveyors not hearing birds among the din of the cicadas, the number of birds in the cicada areas would drop, while the number of birds in the non-cicada areas would stay the same. If the cicadas were driving the birds away, there would be fewer birds near the cicadas and more where the weren’t cicadas. Finally, if the number of birds declined similarly in areas with and without cicadas, then some other factor was at work.

The researchers used BBC data from the 1987 and 2004 emergences of Brood X, the periodical cicadas that live in the Mid Atlantic states. The data included whether or not the surveyors could hear cicadas at each data collection point.

They found that the number of birds declined similarly in areas where there were cicadas and areas where there weren’t cicadas within the Brood X emergence region. The findings strongly suggest a true decline in birds during these years.

What is causing that decline? The researchers could only speculate. But perhaps the mysterious environmental trigger that leads the cicadas to emerge every 13 years in the South, and generally every 17 years in the North, also influences the bird population decline — giving the cicadas the best chance of creating a new generation, without winding up as an avian snack.

Read the whole paper on the Cornell researcher’s Web site, here.

Read more about the current cicada emergence, here, in USA Today and on Nashville Public Radio.

Photo: Brood XIX cicada in Chapel Hill, NC, taken by Philip N. Cohen

More Cervid Contraception: GonaCon and Elk

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Rocky Mountain National Park was the site of a study of the effectiveness of GonaCon, a wildlife contraceptive in elk. The park has quite an elk problem. With no predators to worry about, the elk eat, wander through nearby Estes Park, stroll the golf course, eat some more, and make lots of baby elk. They have altered the park’s ecosystem by not allowing willows and aspens to grow.

Culling is the foundation of the park’s plan to reduce the herd, but of course, that bothers some people. A lot. This excellent story in New West has all the details on the elk in the park and the GonaCon study.

If you are unaware or need a refresher of why wildlife managers would welcome an effective and inexpensive wildlife contraceptive, here are a few articles.  New Jersey Hills/The Progress. (Utah) Standard-Examiner. The New York Times.  (And yes, that’s a little heavy on the New Jersey deer, but no place does suburban deer quite like NJ.)

Read more in New West.

Photo: A bull elk, I don’t know where. Probably not in the Rocky Mountain National Park. Credit: Gary Zahm, courtesy of US Fish and Wildlife Service

Deer Contraception in Maryland

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Maryland has approved the use of the contraceptive GonaCon for white-tailed deer. It is the first state to do so. The deer must be sedated so they can be injected with the drug, and EPA regulations require the treated deer to be tagged. (Hunters are warned not to eat the meat of the treated deer.) The estimated cost of treating each deer is $1,000. Because of the expense, the treatment is not expected to be used often, and then only in suburban and urban areas under special circumstances.

The Cumberland (Md.) Times-News reported the story. NBC News in Washington has a news brief based on the story.

The USDA has a fact sheet on GonaCon. It is listed as the producer of the drug in the EPA’s fact sheet. The USDA fact sheet notes: “In 2006, the regulatory authority for contraceptives for wildlife and feral animals was moved from the U.S. Food and Drug Administration to the U.S. Environmental Protection Agency (EPA).” The USDA fact sheet has links to further information on GonaCon.

GonaCon can be used in other mammals, and has been tested in ground squirrels in California.

Photo: Steve Hillebrand, courtesy US Fish and Wildlife

State Wildlife Biologists Wanted for Bat Survey

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Mobile bat detector
A coalition of federal and state agencies is looking for wildlife biologists to lead and organize acoustic surveys of bats in all 50 states. (Actually, the program has at least some data from 24 states, but only New York is thoroughly covered, so more leaders are needed just about everywhere else.)

The coalition hopes to gather general population data on bats, particularly as these animals face two threats: white nose syndrome, and wind power development. Surveys specific to the sites of those threats don’t give needed information about bat population trends in general.

The survey protocol uses your real-time recording bat detector (such as those from Anabat or Binary Acoustic Technology) mounted to the roof of a car (with materials available cheaply from home improvement stores). The trickiest part may be planning the transect, which should be 20 to 30 miles long, and driven at very close to 20 mph. If it is a loop, it should be wide enough so that you are unlikely to encounter the same bat twice. The surveys should take place at sunset, on evenings that are over 50 degrees F, with low wind, and no rain.

Organizing a statewide survey is easy, say the organizers. New York covers the entire state with 80 volunteers and one coordinator. They cover 50 transects, two or three times a year.

Finding the citizen volunteers has been easy, but finding qualified wildlife biologists to lead state programs has been more difficult. Susi von Oettingen, of the US Fish and Wildlife Service, said in her presentation on the survey project at the Northeastern Fish and Wildlife Conference last month that state wildlife biologists are the ideal leaders.

Free training materials are available to leaders. For more information on the project, and how to get involved as a leader, visit the project’s Web site, which includes a video of a presentation of the project, plus a PowerPoint presentation.

Photo: Courtesy New York State Department of Environmental Conservation and the bat survey coalition

State Wildlife Biologists Wanted for Bat Survey

Posted on by
2
Mobile bat detector
A coalition of federal and state agencies is looking for wildlife biologists to lead and organize acoustic surveys of bats in all 50 states. (Actually, the program has at least some data from 24 states, but only New York is thoroughly covered, so more leaders are needed just about everywhere else.)

The coalition hopes to gather general population data on bats, particularly as these animals face two threats: white nose syndrome, and wind power development. Surveys specific to the sites of those threats don’t give needed information about bat population trends in general.

The survey protocol uses your real-time recording bat detector (such as those from Anabat or Binary Acoustic Technology) mounted to the roof of a car (with materials available cheaply from home improvement stores). The trickiest part may be planning the transect, which should be 20 to 30 miles long, and driven at very close to 20 mph. If it is a loop, it should be wide enough so that you are unlikely to encounter the same bat twice. The surveys should take place at sunset, on evenings that are over 50 degrees F, with low wind, and no rain.

Organizing a statewide survey is easy, say the organizers. New York covers the entire state with 80 volunteers and one coordinator. They cover 50 transects, two or three times a year.

Finding the citizen volunteers has been easy, but finding qualified wildlife biologists to lead state programs has been more difficult. Susi von Oettingen, of the US Fish and Wildlife Service, said in her presentation on the survey project at the Northeastern Fish and Wildlife Conference last month that state wildlife biologists are the ideal leaders.

Free training materials are available to leaders. For more information on the project, and how to get involved as a leader, visit the project’s Web site, which includes a video of a presentation of the project, plus a PowerPoint presentation.

Photo: Courtesy New York State Department of Environmental Conservation and the bat survey coalition

Upcoming Research Round-up

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The New York Cooperative Fish and Wildlife Research Unit is planning two black bear studies.One will study New York’s black bear population as it moves into new areas. GPS-collared bears will be tracked in core habitats and fringe areas. The researcher will compare how bears chose habitats and when they use habitats in the core areas to where to when they are active in newly populated areas. Another study will use DNA to estimate the population of black bears in those newly-occupied regions of the state. The study will use mitochondrial DNA markers from hair samples snagged on barbed-wire snares for a mark-and-recapture survey of sorts. More details are available in the NY Cooperative Unit’s newsletter.

In Oklahoma, biologists with the Oklahoma Department of Wildlife Conservation are planning a big study of bobwhite quail to gather the data needed to try to rebuild bobwhite quail populations in the Rolling Plains in the western part of the state. The study will investigate toxins, weather, parasites, and predators as potential causes of the bobwhite quail population’s decline. The biologists will coordinate their efforts with biologists in west Texas, since the Rolling Plains region crosses state lines. Read more in the Oklahoman. More info on quail in the Rolling Plains is available from the Rolling Plains Quail Research Ranch (which is in Texas).

Photos: Bobwhite: Dan Sudia, US Fish &Wildlife; Black bear, US Fish & Wildlife

Stats on two threats to birds

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A study of a Wisconsin wind farm found that raptors mostly avoided the site, resulting in a big reduction of raptors in the area after the turbines went up. It also found that red-tailed hawks and turkey vultures took the most risks near the turbines, although red-tails were the only raptors found dead in the wind farm. Read the open-access article in The Journal of Applied Ecology here.

Also in the Journal of Applied Ecology, Dutch researchers found that birds breeding near noisy roadways had smaller clutch sizes than other birds. When the roads were noisy in April, the birds had fewer fledglings, regardless of clutch size. The species studied was Parus major. The paper, again, open access, is here.