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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Fifty-four bitterns were among the 4,244 dead animals found in a 3-year study along Highway 49. © Jack R. Bartholmai
Fifty-four bitterns were among the 4,244 dead animals found in a 3-year study along Highway 49.

© Jack R. Bartholmai

June 2005

Deadly crossing

A stretch of highway through Horicon Marsh takes its toll on wildlife trying to reach habitat on the other side. Can we bypass the damage?

Scott Craven
and Jamie Nack


Lots of traffic down the highway and across it
Options to reduce road kill losses
You've got a friend

Road kill! To most drivers the term conjures up images of mangled deer carcasses along the roadside, yellow signs sporting the black outline of a buck, or the occasional headline reporting human death or injury when deer and car collide.

As described in the October 2004 issue of this magazine, deer-vehicle collisions are a serious reality of driving in Wisconsin. Progress on strategies to reduce crashes has been countered by more roads, more cars and higher speeds.

Road-killed deer are costly and traumatic on both sides of the bumper, but they don't endanger deer populations from a biological or wildlife management standpoint. Repair costs and human safety aside, the loss of 20-50,000 deer doesn't raise much concern given that hunters take ten times that many, and we are told that even those harvests are not enough to restore ideal population sizes, given the herd size. But what about some 500 other species of wild animals also in harm's way on the highway? What about damage to birds, mammals, reptiles and amphibians killed by cars and trucks?

Tens of thousands of small creatures create little more than a thud or bump when they are in the wrong place at the wrong time. Most drivers probably don't even notice the garter snakes, songbirds or frogs killed on impact with tires.

If you doubt the magnitude of the problem, do your own survey! Simply keep your eyes open for road kill as you drive to work or head out on vacation. Wisconsin naturalist and historian A. W. Schorger did just that as he made regular trips from Madison to Freeport, Illinois from 1932 to 1950, when the number of vehicles on the road was relatively small and wildlife habitat was much more abundant than now. In 97,020 miles of driving, Schorger recorded 4,939 dead birds alone, representing 64 species! Losses are so common that there is even a satirical field guide to "Flattened Fauna" to help identify road-killed animals. How serious are the losses and can anything really be done to reduce the carnage?

Lots of traffic down the highway and across it

Signs warning of wildlife crossings and reduced speed limits seem to be largely ignored by the driving public. Fences and other barriers, underpasses, overpasses and high-tech motion detectors are expensive. Despite the obstacles, many citizens and biologists believe the problem needs attention and there are calls for creative solutions, especially along stretches of Wisconsin's highways that are notorious as death traps for wildlife.

One such stretch is the 2.5-mile segment of Wisconsin Highway 49 that bisects the northern end of the Horicon National Wildlife Refuge just east of Waupun. And one such group of concerned citizens and biologists is an ad hoc task force that came together in early 2004 to tackle the Highway 49 problem head-on. Wildlife refuge staff, Wisconsin Department of Transportation staff, UW and Wisconsin DNR biologists and citizens from the Friends of Horicon National Wildlife Refuge continue to meet, hopeful of finding a workable solution to the problem.

It is definitely a problem that warrants that kind of attention, says Carol Sykes of the Friends group. Over 32,000 acres in size, Horicon is the largest freshwater cattail marsh in the U.S. and is a critical rest stop for thousands of migrating ducks, geese and shorebirds. The marsh area is also a magnet that attracts visitors for whom the Highway 49 lookouts and roadsides are not just a commuting route but a destination. The Horicon Marsh complex is recognized as a Wetland of International Importance, a Globally Important Bird Area and a unit of the Ice Age National Scientific Reserve. Each year over 400,000 people visit Horicon National Wildlife Refuge on the northern two-thirds of the marsh.

For the past three years, refuge biologists and volunteers have systematically searched the road in all seasons for road kill. During the three-year study, they found 4,244 dead animals, representing 91 species or species groups (such as "frogs").

You've got a friend
To find out more about Horicon Marsh events or receive informational brochures, leave a message for The Friends of Horicon National Wildlife Refuge, at (920) 387-2658, ext. 17. Calls are checked regularly by a member of the Friends group and returned as soon as possible.

"In the spring, there can be days where the number of dead frogs is too numerous to count," says Wendy Woyczik, refuge wildlife biologist Moreover, the numbers of dead animals we can document should be considered as the absolute minimum because an unknown number of carcasses are removed by scavengers, fall undetected in the grass, or are carried away on the grilles and bumpers of the vehicles that killed them, Woyczik says.

The recent research shows that about three-quarters of the total mortality consists of frogs, toads and muskrats, all extremely common animals in that wetland environment, yet many other popular, charismatic and uncommon species are also represented. Thankfully, there are no state or federal, threatened or endangered species on the list of dead species recovered to date. However, visitors to the refuge would certainly miss the chance to observe the 54 least bitterns, six river otters and 27 yellow-headed blackbirds found in these road kill surveys.

Options to reduce road kill losses

Highway 49 presents a deadly combination of risk factors for wildlife. First, it bisects a continuous expanse of several thousand acres of managed wetlands; ideal wildlife habitat. Second, the stretch in question is straight, flat and presents a tempting opportunity for drivers to "put the hammer down." Third, there is simply a lot of traffic, including large trucks. Highway 49 has been a key link between Highways 151 to the west of the marsh, and 41 to the east of the marsh and between Waupun and other area communities. However recent improvements to Highway 151 west of the marsh may reduce truck traffic. Even so, simple probability suggests that an animal crossing the road stands a good chance of meeting an oncoming vehicle.

Even a tough snapping turtle isn't aromored well enough to take on the traffic at Horicon National Wildlife Refuge in Dodge County. © Jack R. Bartholmai
Even a tough snapping turtle isn't aromored well enough to take on the traffic at Horicon National Wildlife Refuge in Dodge County.

© Jack R. Bartholmai

The task force has discussed many possibilities ranging from expensive options like relocating Highway 49 to the north of the refuge, to relatively inexpensive options like more warning signs and creating simple barriers to animal movement. Solutions like culverts and underpasses used in similar settings are not as simple to install in the Horicon situation. Highway 49 is only a foot or two above the roadside water level and it serves as a water level control dike between units of the refuge that are intentionally managed to provide variable water levels to meet the needs of wildlife. Water levels are managed at different times of the year and on multiple-year cycles to provide nesting habitat, feeding areas, loafing areas and staging areas for a diversity of wetland wildlife. A simple culvert would not work unless the roadbed is raised, because it would drain the water impounded on the north side of the highway.

The ad hoc task force will continue discussions and hopes to encourage steps to reduce road kill problems this spring and summer including a proposed sign on Highway 49 drawing attention to the problem, but they need help! Finances are always an issue, but beyond that we need a fundamental change in driving behavior in this unique area. Despite a genuine and widespread empathy for wildlife, we all seem to be more strongly bonded with our cars and are "driven" by a sense of urgency to get to any given destination.

Driving on Highway 49 as it passes through the marsh is more than just another few minutes on the road, it represents an opportunity to experience one of the great wildlife viewing sites in the United States. To keep it that way, please, slow down and travel no faster than the posted speed limits. Enjoy the view, and watch for wildlife on the road, roadside, or approaching the road corridor. Drivers should reduce their speeds to allow enough reaction time to brake if they see an animal on the road. Be especially observant during the early morning, evening and nighttime hours when animals are most active. As the Humane Society of the United States' national campaign says, "Give Wildlife a Brake!"

If you decide to pull off onto the shoulder, pull all the way off the road. Use your turn signal when pulling off and on the road, and be very careful to watch for fast moving traffic. Stay in your vehicle! Birders can use simple two-way radios to communicate sightings between vehicles without getting out of their cars, trucks and buses. Promote the idea of using the vehicle as a blind, too. Stay on the same side of the road and do not cross the roadway! Alternative viewing sites off the highway are available at the east and west ends of Highway 49 where it enters and leaves the marsh.

Whether Highway 49 is your destination or a byway on your journey, take the time to slow down, enjoy this unique corridor and keep an eye out for the smaller creatures trying to have a safe trip traveling across the road.

Scott Craven is a wildlife specialist and Jamie Nack a wildlife outreach specialist with the Department of Wildlife Ecology at the University of Wisconsin-Madison. Jon Krapfl and Molly Stoddard with the U.S. Fish & Wildlife Service and Carol Sykes from Appleton also provided information for this story.