The need to provide connecting corridors for wildife is more important than ever with our human population on the rise and now up to 330 million,,,,,,,,,,,,,,,,with 400 million projected by 2050!,,,,,,,,,,,,This increased "human load" will witness a large increase in cars and time spent on highways............Additional highway underpasses and overpasses will be so needed to move the gene pool of wild creatures from region to region so as to not "bottleneck" them up in a given locale with its resulting inbreeding leading to birth deformites and death...............It is now demonstrated via the existing "culverts" across roads spanning all regions of the USA that Grizzly Bears, Wolves, Elk, Moose and Deer favor high, wide and open overpasses while Pumas, Black Bears, Martens and Coyotes favor long, low and narrow underpasses............Limiting human use of both type culverts is also key in encouraging wildlife usage........ We also must exhibit patience once these culverts are created as it can take months and even years for wildlife to adapt and trust these connective arteries to be "safe-haven" crossings for them

From: Meril, Rick
Sent: Tuesday, March 22, 2016 4:59 PM
To: Meril, Rick; Larry Brown; Kim Lamorie; fixequip@yahoo.com; Mary Wiesbrock; sheila@bos.lacounty.gov; sarah@sen.ca.gov; senator.pavley@sen.ca.gov
Subject: RE: certain animals prefer overpasses,,,,,,,,,,,,,,,others underpasses

Banff National Park

Frequently Asked Questions

Why do animals cross the highway?
Do highway fencing and wildlife crossing structures work and do they reduce wildlife-vehicle collisions?
Do animals prefer underpasses or overpasses?
Is use of the crossing structures by wildlife changing over time?
Does human use of a wildlife crossing affect how animals use them?
How do small animals get across the highway?
What is the greatest threat to healthy wildlife populations?
How do we know where to put future wildlife crossings?
Why are animals still occasionally killed on the highway? 

Principles of Road Ecology 
10 Quick Facts about Wildlife Crossing Structures  

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Why do animals cross the highway?

Animals need to cross the highway to search out companionship, mates, food, shelter, and in some cases, to escape predators.

Do highway fencing and wildlife crossing structures work and do they reduce wildlife-vehicle collisions?

It took up to five years for some wary species, like grizzly bears, to start using wildlife crossing structures; however, most species are now using them to safely cross the Trans-Canada Highway (TCH). Since fencing and crossing structures were first constructed, wildlife-vehicle collisions have dropped by more than 80%.

Puma using underpass

Do animals prefer underpasses or overpasses?

Wildlife use underpasses and overpasses alike; however, when given a choice each species seems to have distinct preferences. Grizzly bears, wolves, elk, moose and deer prefer crossing structures that are high, wide and short in length, while black bears and cougars tend to prefer long, low and narrow underpasses.

Black Bear using underpass

Is use of the crossing structures by wildlife changing over time?

Yes. As wildlife populations fluctuate, the number of occasions individuals of a particular species use the crossings also rises or falls. We have also learned that some animals need time to adapt to new structures on the landscape. For example, overpass use gradually increased for grizzly bears, cougars, and wolves over the first five years of monitoring.

Does human use of wildlife crossings affect how animals use them?

Yes. When people use crossings, animals tend to use them less. Human use of overpasses is prohibited in Banff National Park.


Bobcat using underpass

How do small animals get across the highway?

Small and medium-sized animals, such as snowshoe hare, pine marten, fisher, porcupine, squirrels and voles, have different requirements for movement across the TCH. Pine martens, snowshoe hare and red squirrels used drainage culverts more often when traffic volumes were high, while coyotes used them less.

What is the greatest threat to healthy wildlife populations?

Road-kill has an immediate and direct effect on a population, easily seen within one or two animal generations. On the other hand, complete barrier effects (i.e. not being able to cross an obstacle like a highway) can take several generations to develop within a population. Barrier effects on a grizzly bear population may take as long as 50 years to measure and can have serious repercussions on genetic diversity and overall health.

How do we know where to put future wildlife crossings?

Over the years, information about where different species are most likely to cross the highway has been collected using:

• radio telemetry monitoring 
• animal tracks in the snow 
• wildlife observations, and 
• road kill hot spots

Wildlife movement models were built using mapping software to predict the most likely locations for wildlife travel across the TCH based on topography and habitat data for five species (black and grizzly bears, wolves, elk and moose). Locations for future wildlife crossing structures were then identified.


Coyotes using underpasses

Wolf using Bannff Park overpass



Why are animals still occasionally killed on the highway?

Occasionally, individual animals do get into the highway right-of-way. Research is currently underway to test the use of "electro-mats" as an additional deterrent to wildlife at certain breaks in highway fencing. An electro-mat will provide a mild 'sting' to the paw, hoof or nose that touches it. While the shock does not harm the animal, it will hopefully encourage it to choose another path away from the highway. 

From: Meril, Rick
Sent: Tuesday, March 22, 2016 3:34 PM
To: Meril, Rick; Larry Brown; Kim Lamorie; fixequip@yahoo.com; Mary Wiesbrock; sheila@bos.lacounty.gov; sarah@sen.ca.gov; senator.pavley@sen.ca.gov
Subject: certain animals prefer overpasses,,,,,,,,,,,,,,,others underpasses

Bear hair study in Banff proves animal highway crossings work

Katie Mast Aug. 11, 2013Web Exclusive

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For three years, researchers from Montana State University spent their summers collecting bear hair. The samples, collected on both sides of the 50 mile stretch of the Trans-Canada Highway that cuts through Banff National Park, prove what the researchers had suspected: wildlife underpasses and bridges were helping enough bears move back and forth across the highway to keep the populations healthy.

The Trans-Canada Highway stretches nearly 5,000 miles acrowss the country, rolling through each of the nation's 10 provinces and connecting the Atlantic and Pacific coasts. The 100 miles that pass through Banff National Park is a blip in the entire stretch of highway, but a potentially deadly obstacle for the wildlife that live in the park. Demand for a bigger, faster road system prompted a widening of the highway in the 1990s. During construction, engineers lined the highway with fencing and built underpasses and bridges for animals to cross, with the theory they would reduce collisions and provide animals safe passage. However, the decision was controversial as there was little data to backup the hunch.

An overpass in Banff National Park, built just for wildlife, helps reduce highway collisions and connect fragmented habitat.

Construction of animal crossings has skyrocketed since they were first implemented in the 1970s, and Rob Ament, director of the Road Ecology Program at Montana State University says that research has shown as much as 80 to 90 percent decrease in vehicle-wildlife collisions in areas with the structures. Yet without proof that wide crossings are crucial to wildlife, planners have been reluctant to keep building them, especially overpasses, which are more costly and time-consuming than underpasses. MSU's bear hair study proves that not only do animal crossings benefit humans, but also that both underpasses and the more expensive overpasses may be critical to some species' survival.

While deadly run-ins with vehicles is a gruesome end for many animals, the fate of about 1 million vertebrates each day, fragmentation of habitat has brought some species near extinction. Whether unable or unwilling to cross a road, animals living on one side that can't encounter animals on the other side means isolation of genes, what biologists call the "island effect."

A wildlife camera captures this bear using an underpass in British Columbia.

The crossings in Banff National Park include two wide overpasses covered in vegetation that helps them resemble the surrounding habitat. Underpasses provide the cover cougars and many small mammals need, while the bridges and overpasses let moose and elk traverse in their preferred open-sky habitats. Cameras at each of the passageways have recorded hundreds of thousands of crossings for many different species, including bears, wolves, lynx, deer, elk and moose. A wolverinemade the news when a camera captured its walk across an overpass, becoming the first such venture recorded for its species. But cameras couldn't help scientists collect data about individual crossings. "We could show that there were a lot of crossings, but what did that mean? Was it one bear crossing 100 times or 100 different bears crossing once?" Ament and the researchers at MSU wondered. Answering this question was critical to understanding overall health of the animal communities.

What the researchers discovered was encouraging. Over the three-year study, 15 different grizzly bears and 17 different black bears used the crossings. While those may not seem like huge numbers, they represent a significant portion of the populations. Using estimates of the populations of grizzlies and black bears in Banff, these individuals represented close to 20 percent of the population for both species. Previous research estimates that, for large mammals like bears, about 10 percent of a population needs to cross back and forth to ensure a healthy ecosystem. Comparing samples from year to year and in different locations, the researchers can begin to construct family trees for the bears and observe genetic diversity in offspring.

To collect the hair samples, researchers set up lines of barbed wire by several of the crossings. As bears passed, the barbs would snag a bit of hair. To learn about the bears' movement once they crossed, the team also set up wires near trees that the bears used as scratching posts. Finally, they doused piles of wood 8.5 miles from the highway with cow blood and fish emulsion, a stomach-turning scent for us but an enticing curiosity for the bears. Again, when the bears came to investigate, barbed wire nearby would help keep track of which bears visited.

Over three years, the team collected more than 10,000 strands of bear hair. In addition to finding out that the passageways helped keep the populations healthy, the researchers learned that grizzlies preferred the wide-open overpasses while black bears primarily used the underpasses. Roughly equal numbers of males and females for both species used the crossings, and the genetic sampling lets biologists know more about the population's family trees. While the team could have chosen any number of species to monitor, they knew there were enough bears to collect significant data and, since scientists are concerned about their declining populations, the data could be relevant in broader studies.

While animal crossings have proven successful in reducing wildlife collisions on highways and, now, in connecting fragmented habitat, they're not the cure-all for animals who need continuous open space to roam. Crossings won't solve the challenges faced along the pronghorn's 120-mile migration by development. And, as editor Jodi Peterson noted, the fences and crossings don't manage to keep every animal off the highway. However, as China develops its highway system at a rate of 5,000 km per year and Mongolia constructs its first paved 

highway, Ament is pleased that these countries are looking to Montana State University for expertise. "We are trying to encourage them to not do it like us," he says, but rather, consider the ecology as an important component to their construction plans.

Katie Mast is an editorial intern at High Country News.

Image of Banff Wildlife Overpass courtesy of Adam Fagen via Flickr.

https://www.google.com/url?rct=j&sa=t&url=http://www.oregonwild.org/about/blog/wildlife-corridors&ct=ga&cd=CAEYASoTNDEyMzIzNDQyMzMwMTUzOTc0NzIaNTZkMWU3ZjE5ZThmOTk5MTpjb206ZW46VVM&usg=AFQjCNFRQ8zLaDVJQULXUrBW_gvr1W-Uow