Wildlife and Ecosystems

The Minnesota Department of Transportation is helping test ultrasonic bat “deterrence devices” at two bridges to help keep the mammals away from such structures when they undergo maintenance and/or repair activity.

[Above photo by the Minnesota DOT]

The agency noted in a blog post that bats like to roost in bridge expansion joints and temporarily preventing such roosting during bridge maintenance repair activity typically requires installing physical barriers that are often difficult to establish effectively, due to the design characteristics of many structures.

More importantly, the Minnesota DOT does not necessarily want to keep bats away permanently from its bridges because bat populations throughout North America are in serious decline. For example, the agency said white-nose syndrome – a fungal disease – has killed more than 5.7 million bats in eastern North America since 2005. On top of that, wind turbines kill hundreds of thousands of bats in North America annually, according to a study by the U.S. Geological Survey.

The Minnesota DOT has worked with the Minnesota Department of Natural Resources and the U.S. Fish and Wildlife Service for the last two years testing battery-operated ultrasonic deterrence devices that reduce bat activity at bridge site when activated, but ensure a quick return of bat roosting activity when deactivated.

“This project was innovative. We worked with a technology that wasn’t really on the market yet for real-world applications in anticipation of its availability,” noted Christopher Smith, wildlife ecologist with the Minnesota DOT’s Office of Environmental Stewardship.

He added that current regulations require shorter maintenance period options during the construction season in order to protect bats – mandating that crews must avoid having bats present during their work, which impacts cleaning, painting, and other maintenance timelines.

“The presence of bats disrupts bridge work timelines and budgets, and work upsets habitation for species struggling to survive,” Smith said.

The Minnesota DOT noted that it hopes to develop a procedure for deploying this ultrasonic bat deterrence technology when needed and determine associated expenses from this two-year research effort.

Further study could consider the technology in different configurations and environments, test the devices at many bridges around the country, and conduct a cost-benefit analysis, the agency added – while also comparing the “relative impact” of acoustic deterrents on specific bat species.

A state government report is calling for increased funding for transportation projects that protect big game habitats and corridors and prevent thousands of vehicle-wildlife crashes each year on Colorado’s roads.

[Above photo by the Colorado DOT]

The Colorado Department of Transportation and the Colorado Department of Natural Resources authored the Big Game Policy Report, subsequently released by Governor Jared Polis (D) on September 29.

A statement from the governor’s office said the report seeks to “prioritize state policy, coordination and investment to support our wildlife and ecosystems.”

The report notes that the effects of climate change, increased industrial, residential construction, plus ongoing infrastructure development increase the number of situations putting wildlife in conflict with people. The most glaring examples of such conflicts are the estimated 4,000 vehicle crashes with wildlife that cost an estimated $80 million each year in Colorado.

The Big Game Policy Report served as a follow-up to an executive order Gov. Polis issued in 2019 directing Colorado DOT to incorporate wildlife protection measures into “all levels of its planning process, to the greatest extent possible.”

The Colorado DOT already planned to make road improvements to U.S. 160 between Pagosa Springs and Durango when it decided to incorporate wildlife protection elements. The busy stretch of highway has been the scene of more than 350 big game-vehicle collisions in the last 10 years as drivers make their way to the Chimney Rock National Monuments.

The project, expected to wrap up this winter, now includes a wildlife overpass and underpass, high-deer fencing, and “jump out” ramps within the two-mile project area. The fencing helps “funnel” the moving herds toward the overpass or underpass, where they can safely cross the busy highway. The earthen ramps are inside the fencing and allow the animals to safely escape traffic.

By including wildlife elements into planned projects, “it gives us a bigger bang for our buck,” said Lisa Ann Schwantes, a Colorado DOT regional communications manager.

“We look at the projects already identified that need to be done, and we overlap them with wildlife projects and marry them together,” she said.

Though incorporating wildlife protection elements into existing planned projects can be cost-effective, the costs still add up. The U.S. 160 project has a total price tag of $12 million, $5.4 million of which include just the construction costs for the wildlife protection features.

The report points out that, while Colorado DOT continues to look for ways to protect big game and drivers from each other, the agency has no dedicated funding source for such wildlife projects – one reason why the new report calls on the state legislature to find new money to support such projects.

“While progress has been made, the General Assembly should prioritize new funding for transportation projects identified by CPW (Colorado Parks and Wildlife) and Colorado DOT that provide a clear benefit to wildlife populations and human health,” the report states.

The Colorado Department of Transportation and the Colorado Parks and Wildlife (CPW) agencies recently completed wildlife underpasses along a rural stretch of Interstate 25 between Colorado’s two largest cities, Denver and Colorado Springs.

[Above photo by the Colorado DOT]

This wildlife mitigation system is part of a $419 million transportation improvement project – known as the I-25 South Gap project – that aims to improve safety and travel on 18 miles of I-25 south of the Denver metropolitan region; a route that more than 87,000 motorists use on a daily basis.

The I-25 South Gap project’s wildlife mitigation system includes four new and one refurbished wildlife underpasses, 28 miles of deer fencing, and deer guards and jump-outs, Colorado DOT said.

Work on the underpasses is substantially complete with 8 percent of deer fencing installed – just in time to shepherd migrating wildlife safely under the interstate this fall. The I-25 South Gap project as a whole, however, should be finished by 2022, the agency noted.

The Colorado DOT and CPW are also now in the process of installing 59 cameras throughout the project’s wildlife mitigation system to help measure success.

Shoshana Lew, executive director of the Colorado DOT, said that these wildlife underpasses – used by bears, elk, and small game animals – are also some of the largest in North America.

“One of [our] core values is safety, and we are thrilled to deliver on this value to all who use I-25 in the area,” she explained in a statement.

“In Colorado, nearly 4,000 animal-vehicle crashes are reported annually, resulting in injuries and fatalities to people and costing an estimated $80 million,” Lew added. “In the I-25 South Gap, it is estimated that one animal-vehicle crash occurs per day. Our wildlife mitigation system aims to reduce these crashes by 90 percent.”

“Colorado DOT met with various agencies, including CPW, early in the planning process to come up with a collaborative solution,” noted Brandon Marette, land use coordinator for CPW’s Northeast Region. “Fast forward from our first collaboration meeting nearly five years ago to today, where wildlife is now using the underpasses that we planned together. There is more collaboration to come between our agencies as we continue to plan and implement strategies to keep both people and wildlife species safe, thus protecting what is unique to Colorado.”

State departments of transportation in various parts of the country have been working on ways to improve wildlife mitigation tactics over the past several years.

In 2019, the Pew Trusts issued a report that highlighted the work states are doing to boost safe passage for wildlife around roadways, while at the same time improving motorist safety.

“Big-game animals in the American West today are increasingly squeezed by growing suburban areas, energy development, climate change, and an expanding road network,” noted Matt Skroch, a manager with the Pew Charitable Trusts’ U.S. public lands and rivers conservation team and author of the report, at the time.

“[Those] factors are threatening the landscape connections that wildlife needs to move to and from their seasonal feeding and breeding grounds,” he added. “To conserve wildlife corridors while reducing wildlife-vehicle collisions in the West, state and local governments need to take the lead on these issues and guide their agencies to effectively link science with policy. Fortunately, this is beginning to happen. From Montana to New Mexico, states are identifying hot spots where collisions occur and linking those areas with the larger habitat conservation needs on either side of the road.”

For example, in April, the construction of the new Rock Creek Bridge to replace a culvert on US-20 recently won an engineering excellence award from the American Civil Engineers Council of Idaho – an award shared by the Idaho Transportation Department (ITD) and Jacobs Engineering. That new bridge now allows wildlife to pass under the highway, reducing the risk of possible collisions involving wildlife and vehicles on the roadway.

The ITD added in a statement that this particular section of US-20 witnessed 64 vehicle-wildlife collisions over the last five years, which totals a “societal cost” of approximately $2 million when adding together the cost of vehicle repair or replacement, medical bills, and increased insurance rates – not to mention the cost to wildlife.

If culverts under a busy state road are clogging a creek and preventing fish from migrating, how do you simultaneously replace the culverts, maintain traffic on the road, and protect the fish during construction?

[Above photo by WSDOT]

This riddle proved a real-life challenge for the Washington State Department of Transportation, which came up with an innovative answer – leave the culverts in place, build a new bridge somewhere else, and move the creek under it.

More than 50 years ago, the agency installed two 8-foot box culverts on State Route 3 over Chico Creek, home to the biggest chum salmon population in Kitsap County. In 2013, a federal court ruled that the abutting culverts were among 1,002 fish barriers in western Washington and ordered their removal by 2030.

The reason is that culverts create a “choke point” for fish – accumulating debris, narrowing the creek, and preventing thousands of salmon from making the annual spawning trek through the creek to the freshwater bay to lay their eggs. Above the creek, about 50,000 vehicles a day drive on SR 3, so a construction plan had to consider travel patterns of fish and motorists.

The WSDOT solution is a $58.3 million design-build project that features new bridges on SR 3 and nearby Chico Way, two realigned ramps, and two engineered creeks beneath the new bridges. The project will keep traffic and fish moving during and after construction.

Crews building a new SR 3 bridge just east of the culverts are simultaneously maintaining traffic volumes by shifting lanes toward the outside shoulders while the center portion of the bridge is constructed. Then traffic will shift again, to the inside shoulders, while the rest of the bridge is finished. Once SR 3 bridge construction is completed, crews will realign traffic lanes with the new bridge.

Meanwhile, crews are building an “engineered creek” that will realign Chico Creek to bypass the old culverts to pass under the new bridge. Construction work to redirect Chico Creek to the new channel will take place during “fish windows,” when construction work will do minimal damage to fish.

The engineered creek includes native vegetation, strategic bends, and elevation changes designed to support “every life cycle of fish,” said Doug Adamson, a WSDOT spokesman. It will feature places for fish to lay eggs and hide from predators, allowing the salmon to “naturally move” from fresh water to saltwater habitats and back again, Adamson said.

The project also includes a new bridge, two realigned ramps, and a second engineered creek at nearby Chico Way. This work will eliminate fish barriers to an unnamed tributary that feeds into Chico Creek by realigning the tributary and giving it a much wider channel under the new Chico Way Bridge.

The entire project, which will improve access to 21 miles of potential habitat, is regarded as one of the most significant fish barrier removal projects in western Washington due to the number of fish involved and because of the cultural impact to the Suquamish Tribe, whose ancestors have inhabited the area for thousands of years.

The project comes 30 years after WSDOT first created a dedicated program to remove barriers to fish under state highways. Since 1991, the agency has fixed 344 barriers, opening a total of 1,161 miles of fish habitat. “We are opening up dozens and dozens of miles for habitat for fish who couldn’t reach these areas since the highways were first built,” Adamson said. “We are making up for mistakes made in the past. We are working to rectify those mistakes to improve the habitat for native fish.”

The Georgia Department of Transportation and the Georgia Association of Conservation Districts or GACD are planning to install 15 pollinator habitat sites in designated locations as part of a joint effort to educate state residents about the important role “pollinators” such as bees, butterflies, and other insects play in Georgia’s agricultural sector.

[Above photo by the Georgia DOT]

“This partnership provides Georgia DOT with the unique opportunity to create a place for families and travelers to get up close and personal with the wildflowers and grasses [to] learn about how they impact the world around us,” explained Felicity Davis, a landscape architect manager with the Georgia DOT, in a statement.

“We carefully considered the locations for these gardens and with pedestrian safety in mind, we determined the best option would be at rest areas and Welcome Centers across the state,” she said.

GACD received grant funds from the U.S. Department of Agriculture’s National Resources Conservation Service to install pollinator habitat sites and promote the further establishment of such gardens by landowners throughout the state. Through a memorandum of agreement, Georgia DOT and GACD entered into a partnership to fulfill the requirements of that grant.

GACD will provide funding to Georgia DOT’s Roadside Enhancement and Beautification Council, with the department installing and maintaining the gardens while GACD provides and maintains “educational signage” about them. The grant requires both agencies to complete the planting work for those pollinator sites by August 2022.
“Pollinator plants and insects not only play a critical role in supporting our state’s environment and agriculture, but with the specific mix of wildflowers and native grass being planted, the gardens will also provide year-round interest and habitat for insects and small animals,” said Mark Masters, GACD president. “We are excited this partnership has come to fruition and look forward to getting the gardens installed.”

State departments of transportation are involved in a variety of pollinator support efforts.

The Tennessee Department of Transportation, along with the Tennessee Department of Environment & Conservation and Tennessee Department of Agriculture, jointly promoted “pollinator health and awareness” in state parks during National Pollinator Week June 21-25.

The three agencies formed a partnership in 2019 to support 64 acres of “pollinator meadows” at eight state parks. Each blooming meadow contains a mix of nectar-bearing plants and milkweed, which sustain pollinators such as bees, moths, butterflies, birds, and small mammals such as bats.

In March 2020, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way.

The CCAA – eventually finalized in April 2020 – provides a “huge boost” for the conservation of Monarch butterflies and other pollinators on a landscape scale, the U.S. Fish & Wildlife Service noted at the time.

“The regulatory protections provided by this CCAA allow transportation agencies to continue vegetation management practices with less concern that these actions will lead to an increase in the costs of regulatory compliance if the monarch is listed under the Endangered Species Act,” AASHTO said in its letter.

In December 2020, the Transportation Research Board highlighted a bevy of resources available to state departments of transportation to support monarch butterfly habitat and migration support efforts.

To that end, a new report from the TRB’s National Cooperative Highway Research Program – Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies – provides guidance for roadside managers to determine the potential of their roadway corridors as habitat for monarch butterflies.

The report also includes several tools and decision-support mechanisms to optimize habitat potential in a manner that is compatible with the continued operation and maintenance of the roadside.

The Tennessee Department of Transportation, along with the Tennessee Department of Environment & Conservation (TDEC) and Tennessee Department of Agriculture (TDA), jointly promoted “pollinator health and awareness” in state parks during National Pollinator Week June 21-25.

[Above photo of Monarch Butterfly via Wikimedia Commons]

The three agencies formed a partnership in 2019 to support 64 acres of “pollinator meadows” at eight state parks. Each blooming meadow contains a mix of nectar-bearing plants and milkweed, which sustain pollinators such as bees, moths, butterflies, birds, and small mammals such as bats.

The meadows also assist with TDEC’s Honey Project, which allows the public to purchase honey harvested annually within each park.

“We are excited about this partnership,” explained Clay Bright, Tennessee DOT’s commissioner, in a statement. “This effort is an excellent way to educate the public about the threats to pollinators and a valuable part of our Pollinator Habitat Programming.” 

On a national basis, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior in March 2020 supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way.

In December 2020, the Transportation Research Board highlighted a bevy of resources available to state departments of transportation to support monarch butterfly habitat and migration support efforts.

To that end, a new report from the TRB’s National Cooperative Highway Research Program – Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies – provides guidance for roadside managers to determine the potential of their roadway corridors as habitat for monarch butterflies. The report also includes several tools and decision-support mechanisms to optimize habitat potential in a manner that is compatible with the continued operation and maintenance of the roadside.

The Illinois Department of Transportation recently resumed statewide roadside mowing operations, now scheduled to help maintain and grow pollinator habitat.

[Above photo by the Illinois DOT]

“We are committed to protecting the environment in the work we do every day,” noted Omer Osman, Illinois DOT’s recently confirmed secretary, in a statement.

“By combining well-defined vegetation management with mowing cycles that preserve sightlines and maximize safety, we can make a positive impact today and for future generations, [as] pollinators play a key role in the state’s ecosystem by aiding in reproduction of flowers, fruits and vegetables,” he said.

Throughout the summer, the agency noted that it conducts two primary types of mowing: Safety mowing, which occurs directly adjacent to the road as needed, and maintenance mowing, which includes areas next to culverts, ditches, traffic control devices and other structures.

The Illinois DOT noted that in recent years it revised its mowing practices to help create and maintain habitat for pollinators – including the endangered rusty patched bumblebee and the monarch butterfly – cataloged in its Illinois Monarch Project Mowing Guidelines for Pollinators.

By mowing at select times and reducing the amount of land mowed, IDOT encourages the growth of plant species such as milkweed, the only food source for monarch caterpillars.

In 2020, the Illinois DOT said it joined in the launch of the Illinois Monarch Action Plan as part of the Illinois Monarch Project, a collaborative effort to help ensure the survival and successful migration of monarchs by increasing and protecting habitat.

Alongside that effort, in March 2020, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior on March 12 supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way. “The regulatory protections provided by this CCAA allow transportation agencies to continue vegetation management practices with less concern that these actions will lead to an increase in the costs of regulatory compliance if the monarch is listed under the Endangered Species Act,” the organization said in its letter. “We see the CCAA as advancing … guidance developed by the Federal Highway Administration on practices to support pollinator habitat.”

Several state departments of transportation are helping bring back the Peregrine falcon from the brink of extinction by providing nesting platforms on bridges – creating a true symbiotic relationship that protects bird and bridge.

[Photo by Michigan DOT.]

By the 1970s, Peregrine falcon populations were nearly wiped out in the United States, partly because of the widespread use of the pesticide dichloro-diphenyl-trichloroethane – more commonly known as DDT – made the falcons’ eggshells too brittle. The ban of DDT helped to re-establish the falcons, which prefer to lay their eggs on ledges at high altitudes.

Meanwhile, state DOTs across the U.S. were battling the corrosive effects of pigeon guano, which can eat away at the concrete and steel on bridges as well as pose cleanup hazards for work crews.

Enter the falcon, which loves to feast on pigeons – or at the very least scare them away.

The Michigan Department of Transportation is one of several DOTs that encourage falcons to nest under their bridges. In 2010, the Michigan DOT placed a simple wooden platform on the Sault Ste. Marie International Bridge across the St. Mary’s River to provide the birds a safe nesting place, according to Dan Weingarten with Michigan DOT’s Office of Communications. So far, the platform has been home for 30 falcon chicks that have hatched, helping locally re-establish the species.

[Editor’s note: You can view a live camera feed of the falcons by clicking here.]

The platform is a win-win for MDOT, which does not want the pigeons and their acidic droppings, and the falcons, who need a high-altitude home for nesting and hunting.

“One of the reasons it seemed like a good fit is they would prey on or scare away the pigeons,” Weingarten said. “It seems to have worked. The pigeons at least moved.”

In 2013, the Michigan DOT installed two more platforms at the Portage Lake Lift Bridge that have produced 24 chicks. Crews have since relocated those boxes to other locations because of bridge repair work, but many other states have active falcon nesting programs on their bridges.

One of the first states to get into the falcon platform business was Virginia, which placed a nesting box on the Coleman Bridge in the early 1990s. Since then, the Virginia Department of Transportation has placed several more platforms on other bridges – work that greatly benefits the falcon population, according to a report from The Center for Conservation Biology.

“Bridges have made a significant contribution to the Virginia peregrine falcon population,” supporting more than 30 percent of the known falcon population in the state, the report noted.

Other states – including Connecticut, Massachusetts, New Jersey, New York, and Ohio – also have built and installed platforms to welcome the peregrine falcon to nest in their bridges. “Infrastructure is a small part of the comeback story of these birds,” Michigan DOT’s Weingarten said. “But it’s definitely played a role in re-establishing them.”