Five Things Everyone Should Know about…Birds, Buildings, and Avian Mortality

1 l Glass is invisible to birds. When birds see clouds or vegetation reflected in glass, they perceive it as open sky or habitat. Also, if they see plants on the inside of a building through glass, or if they see completely through to the other side of a building, they don’t recognize that there is a solid surface in front of them.

2 l Timing and location increase collision risks for birds. When birds are in close proximity to expanses of glass that reflect habitat, they are in a dangerous situation. This can occur when birds are foraging during the day any time of the year. It can also happen during migration, when many bird species launch into long flights around sunset; they fly for several hours and then land to rest and refuel. When they land near houses in unfamiliar territory, they risk running into glass as they search for food or fly toward reflections of what they typically use for cover from predators and weather.

3 l New buildings present opportunities to decrease collision related bird deaths. With new construction, a good way to design a bird-friendly home or commercial building is to use glass that has patterns etched into it, which breaks up reflected habitat images. This is called fritted glass; an added benefit is that it also helps control heat and light. For existing buildings with large glass expanses, films can be applied that decrease reflectivity. A great source for more information is

4 l Bird feeder placement matters. One best practice is to put feeders relatively close to a house or building. This may seem counterintuitive, but this way, when birds leave the feeder suddenly because they are startled, they can’t build up enough momentum to hurt themselves if they mistake nearby glass windows for habitat. Placing netting between feeders and windows is another good solution. Also, because birds can perceive ultraviolet (UV) light, window decals have been developed that reflect the UV portion of the electromagnetic spectrum. Birds can see these extremely well, but people cannot, and sunlight still passes through. These decals need to be reapplied frequently because they degrade in sunlight. Other ways to break up habitat images are creating patterns with washable tempera paint and installing Acopian BirdSavers, which are evenly spaced nylon strings that hang in front of window glass.

5 l Birds face many risks beyond architecture. Buildings and glass are not the only major hazards for birds. Habitat loss is the primary factor causing avian mortality. Beyond that, best estimates point toward cats as the biggest direct mortality factor caused by humans. Building collisions are right up there at number two. Other mortality sources from humans include collisions with automobiles and communication towers.

Anna Pidgeon is an associate professor in the Department of Forest and Wildlife Ecology.

Into the Woods with FWE

Regal hemlocks tower overhead, fragile ferns blanket the forest floors and ribbons of sunlight break through the canopy. That may sound like paradise, but for CALS forest and wildlife ecology students, it’s a school day—with the forest as a classroom.

Every summer the Department of Forest and Wildlife Ecology offers students a weeks-long opportunity to learn among the trees at the CALS-based Kemp Natural Resource Station in Woodruff. In odd-numbered years, a field camp focuses on wildlife ecology. And in even years students can participate in a Forest Resources Practicum, affectionately known as “Forestry Camp.” The three-week course allows young foresters to see what a career in forestry entails while learning essential skills from forestry professionals.

Last summer’s Forestry Camp followed the established tradition. The class is divided into teams of four, and each is assigned a “compartment,” a 200-acre tract of rich woodland in the Northern Highland American Legion State Forest. Throughout the course, teams learn all about their plot—essentially, forest ecosystem structure, function, processes and services—by surveying the vegetation, soil, animals and, of course, the trees.

Along the way students develop the knowledge to conduct a comprehensive forest resource assessment. Subject areas include basic field skills, plant identification, GPS & GIS, timber cruising, forest soils, wildlife identification and survey methods and forest habitat classification.

Instructors guide students as they work, visiting individual teams in the woods.

“Field visits often take an hour or two because they become deeper conversations about the history of the forests and the various components of the ecosystem,” says professor Volker Radeloff. “Camp days end up being long days!”

All of that work pays off with invaluable experience and a slew of lifelong memories. Student John Joutras recalls the day he and his team got stuck in the middle of the forest during a rainstorm.

“One of my teammates said, ‘You know you’re a real forester when you’re bushwhacking through the woods in the pouring rain.’ Sure, that might sound kind of miserable, but it was actually really fun,” says Joutras.

Hiking from dawn to dusk would feel like a full day to most, but students refused to stop there. After dinner, activities continued with canoeing, campfires and even more hiking.

During the final week, students summarized their results and conducted a final project based on their own and other teams’ data. But the true value of the course can’t be quantified through a final project or grade, students say. Rather, forestry camp motivates students and fuels their passion for the outdoors while they build lasting relationships with instructors and, of course, each other.

“The real challenge isn’t any individual part but finding a way to tackle it all as a team,” says Joutras. “I found that invaluable.”

-Gilliane Davison

Interested in supporting this program? You can make a gift to the Department of Forest and Wildlife Ecology Field Camps and Experiences Fund.

Candid Camera


























Zuckerberg hopes that through Snapshot Wisconsin, biology can join the ranks of such disciplines as meteo- rology that collect data continuously. “Collecting biological data tends to be very difficult,” he explains. State-of-the- art radio tracking can follow only a few individuals. Ecologists want to see how species respond across broad stretches of space and time.












“When you have folks who are engaged in the process in more depth, and maybe helping to drive some of the questions, or helping to partici- pate in the interpretation of the data, that’s where you’re starting to see some of these community-level outcomes,” says Christine Anhalt-Depies, who is currently pursuing a PhD in wildlife ecology.





It’s these modern times that make Snapshot Wisconsin so fascinating.








Five things everyone should know about… Sloths

1) A sloth is not a sloth. There are two types of tree sloths that diverged roughly 20 million years ago—two-toed and three-toed sloths, so named for the number of digits on their forelimbs. They differ greatly in what they eat, when they’re active, the trees they use, how far they move and even their mating systems. In a nutshell, two-toed sloths are generalists, using a wide variety of habitat types and resources, while the three-toed sloth is much more specialized, eating leaves from just a few species of trees, and even spending the majority of their lives in just a few individual trees.

2) They are extremely low-energy. Both types of sloths have slow metabolisms, but the three-toed sloth has the lowest energetic needs of any mammal ever recorded. Sloths achieve this by not moving very much, and also by letting their body temperatures fluctuate with outdoor temperatures. In terms of calories, a single potato is all a three-toed sloth would need each day to survive (if sloths actually ate potatoes).

3) Constipation is a way of life. Sloths consume plenty of fiber in the form of leaves (three-toed sloths) and a variety of leaves and fruits (two-toed sloths). Yet these foods are digested so slowly that sloths need to pass feces and urine only about once a week. Three-toed sloths climb down to defecate at the base of their host trees—practically the only time they leave the canopy.

4) The sloth is a miniature ecosystem. And understanding that ecosystem helps clarify sloths’ odd bathroom behavior. Sloths host a dedicated species of algae in their fur as well as scores of flightless “sloth moths” that depend on the sloth’s defecation descent for reproduction. The moth lays eggs in the sloth’s dung and then returns to the sloth’s fur. After the eggs hatch, the caterpillars feed on the dung, become moths, and the moths find—during the only brief moment in their lifetime that they can fly—another sloth to live on. When the moths die, their bodies are decomposed by fungi and bacteria in the sloth’s fur. The products of this decay, nitrogen in particular, provide fertilizer for the algae, which the sloths eat—thus adding nutrients to their diet.

5) Made for the shade. As tropical forests in Central and South America are cleared for agriculture and other uses, sloths (like many other species) need to find or adapt to new habitats in order to survive. Our team studied sloth populations at a large shade-grown cacao plantation in Costa Rica. With its diverse overstory of native trees, the plantation provides suitable habitat for sloths—especially two-toed sloths—and seems to point the way to at least one kind of farming that can benefit sloths and other native tropical animals.

Jonathan Pauli and Zach Peery, professors of forest and wildlife ecology, have studied sloths in Costa Rica since 2009.

PHOTO: Jonathan Pauli watches after releasing a two-toed sloth in Costa Rica
Photo courtesy of Jonathan Pauli

For the Birds







































Russia: Monitoring Russia’s “rewilding”

Doing fieldwork in the remote wilderness of Russia isn’t for the faint of heart. There are long distances to travel on deeply rutted roads, bleak outpost towns with meager accommodations, and bears and wolves to contend with. Plus—in the case of visiting American scientists—the constant presence of an armed guard who wasn’t there to protect them from large carnivores. “

He was there in case we encountered illegal poachers,” explains forest and wildlife ecology (FWE) professor Volker Radeloff, who has been visiting Russia in a research capacity for a dozen years, most recently with his fellow FWE professor Anna Pidgeon.

According to the duo (who are married), the opportunity to visit two of Russia’s protected areas— the Kologrivksi Forest northeast of Moscow and the Caucasus Mountains in the south—is worth the trouble.

That’s because Russia offers a unique case study for conservation scientists interested in studying the impact of land use changes on wildlife populations. After the fall of the Soviet Union, citizens abandoned the state’s collectivized farms, leaving many of the agricultural fields to revert to a more natural state—and opening up new space for animals to live and roam.

“Their forests are regrowing and their wildlands are coming back, which is something we don’t see in many other places on the planet—especially at that magnitude,” says Radeloff.

Radeloff, an expert in using satellite imagery to monitor land use changes, can look at his remote sensing data and see that forests are expanding in Russia. But the images don’t tell Radeloff and Pidgeon much about what’s happening “on the ground” with local wildlife populations. For that, they need to partner with Russian scientists, working with them on their turf.

As an example, while satellite imagery can help identify promising habitat for the reintroduction of European bison into new areas within the Caucasus Mountains, many other factors will determine a herd’s ultimate success.

“We identified an area that looked like good habitat, but the local scientists made it quite clear that this would not work because of the human context,” says Radeloff. “They told us the bison would all be shot there within a week; they’d never survive. That’s the kind of information we need that we cannot learn remotely and that nobody is publishing about in scientific journals.”

That “human context” is a significant factor, even within the nation’s protected areas. Animals are hunted for food by locals and for trophies by affluent sportsmen. In the southern Caucasus Mountains, ibex, a type of wild goat, are killed for their horns, which are used as wineglasses during traditional Georgian wedding ceremonies. The Saiga antelope of the Kalmykia are likewise poached for their horns, which are sold on the Chinese medicine market. These forces must be factored in.

Trips to Russia also enable Radeloff and Pidgeon to develop important scientific relationships. They regularly host Russian conservation scientists in their Madison labs, giving visitors the opportunity to work on short projects that can aid their efforts back home in Russia.

“Both of us are interested in capacity building, particularly in countries where the resources or training may not be quite as comprehensive as it is here in the United States,” says Pidgeon. “These relationships lead to a cross-pollination that benefits both sides as we work to study and support wildlife populations in Russia.”

Keeping Track of Wolf Deaths

Tim Van Deelen, a CALS professor of wildlife ecology, specializes in the management of large mammals, including population estimation and dynamics, hunting, interaction of deer life history and chronic wasting disease—and, not least, the growth of Wisconsin’s wolf population and its effects on white-tailed deer.

As this year’s wolf hunt season opens in Wisconsin, we talked with him about a hidden and disturbing topic: illegal killing, which Van Deelen says may have increased in recent years. Much of the data on this subject, he says, comes from work by his former doctoral student Jennifer Stenglein MS’13 PhD’14, who is now a wildlife researcher with the Wisconsin Department of Natural Resources.

Can you give us an idea of how wolves die?
As we know from radio collaring data, wolves die for a variety of reasons. Wolves in Wisconsin have relatively high mortality rates, and that probably has to do with the fact that they’re living on a landscape that’s much more highly impacted by humans than, say, northern Canada or Alaska. We have higher levels of wolves getting hit by cars, especially as they begin encroaching parts of central and southern Wisconsin where we have higher road densities.

Wolves are also territorial, so on the margins of their pack territories or where there are territorial disputes between packs, wolves will kill each other.

Wolves die of disease. We’ve had deaths due to parvovirus and mange. Wolves sometimes starve to death if they can’t get enough prey or if they’re old or injured and otherwise inefficient as hunters.

There’s also a fair amount of unexplained mortalities that we have from radio tracking data.

Can you elaborate on that?
We have radio-collared wolves that outlive the radio collars—that is, they outlive the battery that powers the collar—so you have a record that starts when the animal is radio-collared and ends when you stop getting signals. Understanding mortality rates at the population level requires you to make some decisions about how you’re going to treat those animals once the record stops.

Research that my graduate student has been doing suggests that a fair number of those animals are dying.

Do you suspect illegal killing?
Well, the problem with illegal killing is you don’t observe it. You can’t point to something and say, “That wolf died from illegal killing,” but you need extra mortality in the system once you explain everything else in order to reconcile the mortality rates that we’re seeing with the reproductive rates that we get from the pup counts and the growth rate that we see from the annual population counts.

So there’s a missing gap in the data of why some animals disappear.
Right. The basic population dynamics equation is very simple. It says that the number of animals born minus the number of animals dying is the net addition or subtraction from the population. If we have a population that we can count every year like we do with wolves—we count them every winter—then we can mathematically fit an equation to that growth using things like observed deaths and estimated reproduction.

When we can’t get that to reconcile, then we need some additional deaths that are unobserved to make the growth rate that we see agree with the mortality and the reproductive rates that we’re measuring.

The suspicion is that many or some of those unobserved deaths are due to illegal killing. Because from our radio tracking data we do have good estimates on the relative amounts of deaths that are due to other things, like being killed by other wolves or dying of disease or being hit on the road.

What would prompt illegal killing?
Human dimensions research done at the Nelson Institute suggests that people living in wolf range have a sense of frustration that many people think traces back to this on-again, off-again listing of wolves under the Endangered Species Act.

We went through a period where the wolves would be de-listed, or there would be movement toward de-listing, and then somebody would step in, the courts would intervene, and the wolves would become listed again.

There’s good human dimensions research in wildlife that says that attitudes toward wildlife tend to degrade when people feel like they have no options for dealing with the problems that those wild animals are causing.

When wolves are put “off limits” because of the Endangered Species Act, then people who are experiencing problems with wolves, real or imagined— their attitudes toward wolf conservation begin to degrade.

That aligns with some of the research that’s been done on this campus suggesting, among other things, that people who are interviewed in the
north say they’d be more willing to illegally kill a wolf if the opportunity presented itself. More people are saying that now than in the early 2000s. That time period aligns with the growing frustration people have experienced over de-listing.

How many unexplained wolf deaths are there?
About 20 to 30 per year, in our best estimate. That’s been from the period 1980 to 2013, where we fit the models. There’s evidence that it’s been increasing recently. By “recently,” I mean within the past five or 10 years.

Can you please elaborate?
During the early part of the growth phase of wolves in Wisconsin (1996– 2002) the wolf population averaged about 200 wolves during midwinter counts. We estimated that about 43 of these would die during the year, and unobserved deaths were likely not needed to reconcile observed popula- tion growth. During the latter part of the growth phase (2003–2012), Wisconsin’s wolves averaged about 600 wolves, and about 138 of these would be expected to die during the year. However, you would also need another 24 dead wolves to reconcile the rate of population growth observed. These 24 would include a mix of natural and human-caused subtractions, including an unknown level of illegal killing. The change from 1996–2002 to 2003–2012 suggest that illegal killing may have increased.

What kinds of conflicts do people have with wolves in Wisconsin?
Probably the most important right now are conflicts with livestock producers. We have a handful of areas in Wisconsin that are hot spots where there’s been sort of long-term chronic depredation by wolves on livestock.

That’s a real problem—and fortunately in Wisconsin, the Department of Natural Resources has a partnership with USDA Wildlife Services. They have professional USDA trappers who can go in, verify whether a calf or a cow was killed by wolves, and then help the landowners either by excluding the wolves from the territory or by trapping and euthanizing the wolves that are causing problems. They’re very professional, they’re very good at what they do, and they’re very successful.

Another problem in Wisconsin is wolves depredating hounds. These are mostly hounds used for hunting bears and smaller carnivores. If you’re running hounds late in the summer, that’s when the wolves are provisioning their pups at rendezvous sites.

The wolves probably interpret that incursion as an invading pack, so they would attack and kill those hounds. That happens, that’s an issue to deal with. DNR has been proactive with trying to identify those areas where depredations have occurred and might be more likely, and warn people to avoid those areas with their hounds if at all possible.

There’s a lot of talk about wolves having impacts on deer in the north. In some places, that’s probably a reality. In some places it might be more perception than reality. At a statewide scale using the harvest statistics, we just haven’t seen a real impact of wolves, but that’s sort of a coarse-filter approach.

We have two deer research projects going, one in eastern farmland and one in the northwest. We actually don’t find a whole lot of wolf predation on adult deer, which would be the mechanism by which wolves would have the most impact on the deer herd. Still, if you’re the unlucky individual whose hunting spot happens to be sitting right on top of a wolf rendezvous zone, you might not be seeing very many deer.

What would you like to see done with wolf management going forward?
One of the unique things about wolf management in Wisconsin is that we’re managing this population now at a pretty high exploitation rate—meaning that we’ve got heavy harvest seasons. Those are designed explicitly to reduce the wolf population.

Harvest management theory would suggest that there’s some danger of long-term instability. I think the most important thing that managers of Wisconsin’s wolf population need to do is keep putting efforts into monitoring the wolf population—tracking population trends, tracking the extent to which wolves live on the landscape. Those are the measurements you can use to identify some sort of instability and then be able to deal with it.

To be fair to the managers, they know that, they’re working on that. We’re collaborating with them to come up with more cost-effective ways to get the sort of information they need to track population trends.


Not Quite Bucky


“We don’t have a clue. We just don’t know much about badgers in Wisconsin,” says Jimmy Doyle, a forest and wildlife ecology graduate student who is studying the reclusive carnivores as part of a joint UW-Madison–Wisconsin Department of Natural Resources (DNR) project called the Wisconsin Badger Study.

The project, which relies on surgically implanted radio transmitters to monitor the movements of badgers living in the southwestern part of the state, represents the first big effort in Wisconsin to better understand these animals. It will shed light on the landscapes where badgers prefer to live, where they prefer to hunt, how far they roam, whether their territories overlap and much more.

But first, Doyle has to find and catch them.

Working with various DNR technicians, he has walked through scores of miles of grassland over the past two seasons looking for dens, setting traps and then coaxing badgers into travel crates. The effort yielded three badgers in 2011 and 12 in 2012.

“They tend to be pretty feisty,” says Doyle. “There’s lots of snarling and snapping.”

Once caught, the badgers are driven to Madison for a health exam and to have a small radio transmitter the size of an AA battery surgically implanted just below the skin at the scruff of their necks. It’s a quick procedure, and the badgers are returned to their dens within about four hours. The transmitters enable Doyle and his DNR collaborators to track the badgers’ movements at night from the comfort of an antenna-equipped truck—without ever needing to get near the animals again.

The project has a second purpose: to help inform DNR efforts led by DNR grassland community ecologist David Sample to protect grassland-nesting birds in the study area.

Wildlife ecology professor Tim Van Deelen, who is Doyle’s advisor, explains the connection. “Grassland birds have this problem in the Midwest where they have to pull off reproduction in a very predator-rich environment—just think of all the small rodents that would love to eat a little bird egg,” he says. “Badgers might actually be good for birds because they might suppress some of those predators—by eating them.”

Class Act: Hardwood and Soft Skills

When CALS sophomore Logan Wells tells you he spends his spare time sawing logs, he doesn’t mean he’s catching up on sleep. He’s actually out in the woods, running logs through his portable sawmill, making lumber for clients—and making money to help cover his college expenses.

Wells’s Smock Valley Timber is more than a business—it’s part of his education. He started it as a hands-on project for the National FFA Organization, the youth program focused on agricultural and natural resource careers, while he was still in high school. Wells enjoyed working the wood and growing the business so much that he opted to enroll in CALS as a forest and wildlife ecology major with an eye toward a career in forestry or forest products.

While practicing and studying forestry keeps Wells busy, the program that sent him into the woods in the first place keeps him even busier. Logan is a state vice president in the Wisconsin FFA Association, representing 24 FFA chapters in Dane, Rock and Green counties.

Much of that work involves going out to middle and high schools, where he encourages FFA members to get active in the program and talks with them about the importance of “soft” skills—a positive attitude, good work habits, teamwork and other traits that can put them on the path to success.

His own high school FFA project helps them understand where a good idea and a good attitude can take them. His timber enterprise paid off in more than money. It earned a top prize in a national FFA competition, which in turn earned him a spot on an agricultural exchange trip to Costa Rica featuring visits to banana, coffee and cacao plantations, whitewater rafting and trips through the rainforest on zip lines and suspension bridges—all very exciting stuff for students to hear about.

“I get to tell them my story and inspire them to do something like that for themselves,” Wells says.