- Just ahead on "This American Land"... the highways that make travel smooth for people can pose deadly obstacles for wildlife on the move.

When engineers and biologists provide a safer option, deer and other creatures are clever enough to choose the right path.

Humans also seek out safety when they're, well, migrating across town.

- Super nice to not have to worry about crossing the road when you're running.

- In big cities everywhere, greenways are magnets for working out, hanging out, and celebrating nature.

- The greenway creates a sense of community.

People get to know each other on the greenway.

- Now meet the king of camouflage.

Scientists need to track these elusive curlews so they can help protect them in the future.

It's a big order for a small bird.

We'll show you their ingenious solution.

So get ready for your close-up.

The herd is on the move, and we're ready for takeoff on "This American Land."

[dynamic music] ♪ ♪ - Hello, and welcome to "This American Land."

I'm your host, Ed Arnett.

And in every show, we've got some terrific stories about protecting America's natural resources-- our landscapes, waters, and wildlife.

And you'll get to meet some of the dedicated people protecting these treasures.

Up first today, we look at one of the biggest threats to migrating wildlife: modern infrastructure.

Deadly encounters between cars and animals are common, but they're not the only threats to wildlife on the move.

In this story, we'll see how some innovative programs are attempting to give nature a fighting chance.

We start in Colorado.

- We have really quite an array of wildlife here because we have a beautiful riparian corridor.

We have a really healthy pinyon-juniper woodland.

And all of it accesses, then, some open meadow space.

♪ ♪ 550 here intersects a movement corridor for our large game species.

And they move from these summer ranges, and they try to access some of the winter forage that they can get at these lower elevations here.

So it presents conflict between our motorists and traveling wildlife.

- So this one must have gotten trapped inside the right-of-way, hit by a vehicle, and was thrown over.

We have about 14,000 animal collisions on our highways every year.

Nationally, 2 million insurance claims for wildlife-vehicle collisions.

- We keep encroaching, encroaching, encroaching.

So we're creating this problem where, essentially, we're making their migratory path impermeable to movement.

So these techniques that the highway departments and the state wildlife agencies are using to mitigate this now is really-- really great for conservation.

- This particular section of road has an average annual daily traffic of around 8,300.

And science has shown that highways with traffic volumes of 9,000 cars a day create an almost permanent barrier to wildlife movement, so we see a lot of collisions on this road.

When we mitigate for wildlife-vehicle collisions on the highway, we provide a whole system.

The system is comprised of 8-foot-high wildlife exclusionary fencing that you can see here on the side of the road.

Inevitably animals will get into the right-of-way, so we always provide deer escape ramps, which you can see, and that allows animals that get trapped within the right-of-way a chance to escape the right-of-way and get back into the habitat.

And then at every access point, we then have to install cattle guard, or deer guards, in this case.

And it basically prevents the animals from walking through the openings that we have in a fence.

All that fencing and the wildlife jump-outs really are tied to the wildlife crossing structures themselves, which allow the animals to safely move underneath the highway.

We pinpointed this where we saw a number of accidents.

They used it--within two weeks of us pulling the construction equipment off the project site, we had animals utilizing this structure.

You want it to be as open as you can possibly get it.

And animals really won't use a structure unless they can see daylight through it.

The crossing structures themselves cost anywhere between $750,000 to $1 million to construct.

But when you are reducing the rate of accidents to the degree that we are, they do end up paying for themselves by the benefit that they provide over a 10- to a 15-year period.

- We're approaching the proposed location for our large game crossing structure for this piece of US 550.

The department is fully aware that we are responsible for trying to eliminate some of the barriers that our transportation infrastructure has created.

- And this is just an example of what we're trying to avoid.

- So this will be a project that will allow us to try to keep these movements in place, enable the wildlife to get to the resources that, unfortunately, this essential highway has blocked and complicated for these animals who've been traveling on this corridor for eons.

- Just like wildlife need to migrate across highways, fish need to migrate upstream through man-made barriers.

- This is a corrugated steel culvert that's been in the ground for approximately five decades.

It's in failure mode, as is exhibited by the torn steel at the bottom of the outlet.

It's a fish passage barrier because of the velocity of the water coming through the pipe.

So they spend their last days on this Earth jumping into a--into a stream that washes them back to where they started.

And they just try and try and try.

They won't quit.

They won't quit until it kills them.

- And they're all blocking salmon and steelhead from reaching their spawning and rearing habitat.

As humans, we've created a lot of impacts across the landscape.

And a lot of that development has had unintended consequences.

But now we know better.

- This is an example of what can be done.

And what you can see is that we've built a roadway that's completely out of the way of the natural process of the stream, bringing in rocks similar to what's in the stream naturally.

And so any fish at any life stage that can make it this far doesn't hit this migratory barrier anymore because the migratory barrier's gone.

It's been replaced by a stream.

- And it's our responsibility to do everything that we can to reconnect habitat so that fish and wildlife can move freely.

- The same superhighway program, what we do is, we locate, identify, and evaluate culverts in this condition-- and we have many of them-- and we put together a plan.

We take this out of the ground.

We excavate a wide enough channel that the stream can flow like a stream, and we build a permanent bridge structure over the top of it.

Now, that permanent bridge structure is built-- they basically are built to last 100 years.

- We started working in 2014 on the actual replacement of the culverts.

Since that time, we've completed 43 projects.

We've reconnected 115 miles of habitat.

We have federal, state, and local partners involved, different agencies and community groups, nonprofit organizations.

We'd certainly like to see the salmon superhighway approach applied up and down the Oregon coast, where salmon and steelhead are threatened and declining.

Now we know the effects that development has had on fish and wildlife in our ecosystems, so we need to collaboratively use our resources to give them the maximum habitat they need to thrive and survive.

- We're in the northern part of the Great Basin of the western United States.

And we're the Wadatika Neme, which is the Water Eaters of Northern Paiute Band.

And our people have retained our Aboriginal rights to hunt and fish.

We had very limited economic resources.

We always have.

And so our people have continued to subsist to a great degree using traditional hunting and gathering practices and beliefs.

We're not trophy hunters, so the value of the animals-- they all have life and personhood, and the taking of their life isn't something to celebrate.

We're taught that we have a reciprocal relationship with them that should remain in balance.

- The population of deer and elk are extremely important to the tribal members here.

It provides us with the tribal first foods.

Yeah, provides sustenance, you know?

My father instilled into me to provide before I eat.

So I provide everybody with meat before I eat.

I link that to just having respect for our elders and those members who cannot hunt.

Jonesboro holds a pretty special place in my heart.

That used to be our go-to spot to shed hunt.

And every year, we'd go back, and I'd harvest a buck or a doe, and so would my family.

And I've noticed the decline in quality of hunting out there.

There's just less-- less animals.

You really notice it.

- We see a lot of mule deer and elk strikes in the area.

20% to 40% declines in the adjacent populations.

We're really concerned that the population's trending towards extinction eventually.

And luckily, because there are these bridges, we're gonna be able to use those bridges and retrofit them so that wildlife can use them as well.

So this is the way the animals would normally come.

They just use the directional fencing into the bridge.

They would likely just become habituated to using these safer passages.

And so that would be something that, you know, populations of deer would be able to learn.

Because these mule deer are so critically important to the tribe, there's a lot of people that are really passionate about trying to find ways to address this.

- Our transportation infrastructure has a profound impact on the natural environment.

And it is our responsibility to offset or mitigate the impacts that we're having to the natural landscape.

- We have to be the voice for the animals that are part of our large ecosystem family in order to help protect them and make sure that they can continue to exist and thrive.

- In cities across the country, greenways are connecting neighborhoods, businesses, and waterways.

These vehicle-free corridors let runners, bikers, and bird-watchers travel at their own pace and explore and appreciate their communities.

At the same time, they're protecting important habitat.

Let's go to Charlotte, North Carolina, where a water cleanup project started decades ago has blossomed into new opportunities for city dwellers to enjoy the outdoors.

- What I love about Charlotte is that it's such a green city.

You can remain in the city and still be in nature.

Let's go outside and warm up.

On Saturday mornings, it's our long run.

So we'll meet pretty early and go out and do whatever distance is on the calendar for the day.

- And they're off.

- It is very enjoyable just to run next to the water and all the green around you.

It's just a long stretch of a beautiful park for me.

- Super nice to not have to worry about crossing the road when you're running.

I also have a dog, so we go on walks here all the time.

She loves seeing the river.

And lots of times, there's, like, ducks in the river.

And she really likes the nature and everything.

- Another big thing for me is that it's a safe route.

So I know that when I'm on the greenway, there's gonna be other people on the greenway.

- The greenway creates a sense of community.

People get to know each other on the greenway... - Morning.

- That perhaps didn't know each other before.

Hi, ladies.

- Hi!

- How are you?

- My name is Gwen Cook, and I'm a planner with Mecklenburg County Park and Recreation.

Some people have called me the Godmother of Greenways.

There are groups that meet to bike.

There are groups that meet to walk.

Neighborhoods are connected by the greenway.

Now we have 64 miles on the ground.

We have another 13 miles of greenway in construction.

So we're moving rapidly on completing our master plan.

It's very exciting to see these come to fruition and to see how people love them and are just waiting for their greenway to appear in their neighborhood.

- These greenways are heavily used, and people really enjoy it.

Well, people need to realize it wasn't always this way.

My name's Rusty Rozzelle, and I'm the Mecklenburg County water quality program manager for Charlotte-Mecklenburg Stormwater Services.

In the '60s in downtown Charlotte, our creeks were literally open sewers-- no fish.

People hated even living along the banks 'cause they smelled so bad.

This creek we're on now is Little Sugar Creek.

Back in the early 1990s, this creek was pretty much void of any aquatic life.

You wouldn't see fish in here.

You wouldn't see much living on the bottom-- pretty much dead.

And nobody knew it was here.

It was covered by trees.

It was not utilized.

And when I started with Mecklenburg County in 1980, the only way you would ever see a creek is at a bridge.

That's it.

Matter of fact, we used to have a saying: cross a creek, take a peek.

That's the way most people would tell us if there was a water quality problem.

The Board of County Commissioners back in 1996 called for a creek use policy where all the waters in the county should be suitable for human contact.

And they put money behind it, and they funded all these special programs.

We've done a lot of things over the past 25 years to try to restore water quality.

We require buffers countywide, so we don't build right up on the banks of the creek.

We improved our floodplain regulations, which kept more development off the banks of the creek.

At the same time, we gave a big boost to our greenway program.

We took what is our most precious natural resource here in Charlotte-Mecklenburg and opened it up to the public.

Now people can walk along these creeks, watch all these cascading waters, enjoy the aquatic life and the terrestrial life-- I mean, deer tracks right here.

You know, there are otters in this creek-- otters.

I've lived here my whole life.

I'm 65 years old.

I'd never seen an otter till I saw one in Little Sugar Creek.

- There's a lot of birds here.

And you never know day one to the next day which one you're gonna get.

Since I'm a hobby photographer, this has given me a lot of chances to take pictures of nature, birds, flowers, vegetation, people.

I've met a few that we have made friends with and see them often walking the greenway.

- Because people are able to get down here next to the creek, they feel an ownership to it.

We all the time get reports from people on the greenway saying the creek looks different today.

And we'll go out there, find the source, and eliminate it.

So we have an army of people watching out.

- We talk about positive impact of a greenway-- the parking lot of the trailhead becomes a node--a connectivity point for that community.

It also provides access for businesses.

- A lot of times, we'll have people visiting from out of town, and they'll, you know, Google search greenway or places to run and go to the greenway.

And then they'll see our store and make their way in here.

- I'm gonna do matcha latte.

My store is located to the newest section of the greenway.

It's about 200 feet away from it, so I'm just looking for more foot traffic of people that are already using the greenway.

So it's a little bit of just, like, bystander advertisement.

Take care.

- Greenways are transportation corridors that are also recreation amenities.

It becomes environmentally positive by people using other means of transportation other than motorized vehicles.

- We've done a lot of good things, but it is very easy to let this slip.

Runoff, when you pave an area or build buildings, water hits that area.

And the water runs into a pipe, and it runs straight to the creek.

What you got to do is, you got to treat as much as possible-- all of it, if possible-- before it reaches the creek.

This section of stream has been restored.

The banks have been laid back.

They've been vegetated.

And this vegetation acts to filter pollutants before it runs down into the creek.

And they also obtain nutrients and water.

But just on the other side of this, there needs to be something between that parking lot and this creek to treat the water.

Another thing is, is the water safe to swim in?

No.

You've got sewer lines along this creek.

And raw sewage can get into the creek.

It gets fixed really quick, but you might not see it, and you might not know it.

- We're always surprised to hear people say that they didn't know there was a creek here before the greenway went in and enjoy seeing that creek, seeing the fish in that creek.

And to be in a big metropolitan area like we are, to have that natural world coming through by the greenways is pretty special.

- You may not be familiar with curlews, but these are grassland birds that are truly masters of camouflage.

Because they're so hard to spot, researchers are attaching tiny satellite transmitters to some birds.

And what they're learning from this tracking data can lead to better decisions about protecting their habitat.

Kris Millgate has our story from Idaho.

- You probably wear a backpack like this when you're hiking.

It holds snacks, water, maybe your coat.

It's easy to remove because it's temporary and it's not trackable.

This next pack you're about to see is attached, and it's trackable, so it's not so easy to slip.

It comes in handy when you're looking for something that is the king of camouflage, the long-billed curlew.

The consistent cover of grass makes curlews nearly impossible to find-- nearly impossible.

Look hard enough and long enough, and you just might see one.

Odds are even better if it's wearing a backpack or, better yet, a bird pack that's trackable.

- Finding an American robin nest is fun when they're nesting, like, in your garage or on your porch.

But it's not hard to find their nest, so the challenge isn't there.

These guys challenge me.

They make me work to find their nest, even ten years in.

They nest on the ground-- very open habitats where you wouldn't be able to just say, oh, I bet there's one nesting there or there.

It all looks relatively uniform, and I think that's part of the design of them being able to camouflage their nests.

Their eggs are monstrous compared to their body, so bigger than a chicken egg.

We've had times where we're standing within 4 or 5 feet of a bird and then finally it flushes off a nest.

They're just, like-- that's what their-- that's their life.

And I've always wondered, like, if it was me, right, and I'm hiding even just from friends playing hide-and-seek in the dark at ten years old and somebody's getting close, like, your heart rate starts to go up, right?

Is that what they're like?

Or are they just so used to being camouflaged and they trust in their camouflage that they're just like, eh, he can't see me.

I don't know.

We've got a number of pairs that are mated pairs that we've put transmitters on both birds.

The female tends to start leaving after a week to two weeks.

We mostly end up with males caring for the young after that two-week point.

Just the outreach value alone of being able to put points on a map and connect here to the northern Gulf of California and say curlews that breed here are wintering there, that's really exciting.

Learning things that managers might use to improve conservation or management on their lands, I really like that.

So it's great to do science, but if all we're doing is science and it doesn't make a difference, what's the point?

For a population like here at the Flat Ranch, you have this awesome grassland habitat that's wet, that's productive.

If we had management that stayed the same for the next 50 years on Flat Ranch but the population started declining, these transmitters give us an idea of where to look... - 1, 2, 3.

- And start thinking about, well, what might be happening in that part of the cycle?

- After each of our shows, viewers ask us, what can I do to help an endangered animal or protect a beautiful river?

Rusty Rozzelle in Charlotte shared with us how greenways can provide safe and enjoyable corridors for people and wildlife in just about any community.

- My advice to other cities would be to see what we've done with our buffer rules, with our water quality rules, and how we've made our streams a priority.

We've protected them, made them cleaner, and then brought the community in to enjoy it.

That's the model.

And it can be reproduced everywhere in this country, and it should be.

- Now here's a look at some stories coming up on our next show.

- 2, 3.

- A colossal effort to save one of the most endangered species on Earth.

- The main issue here is trying to protect the North Atlantic right whale.

So any pot fishery that has lines going from the bottom to the surface presents an obstacle.

- New ropeless fishing gear can keep these right whales from deadly entanglements.

- I got him!

He's in.

He's in.

Back up.

Back up.

- Entanglement can cause horrible abrasions, starvation, amputation.

The worst possible outcome is death.

- I've been fishing in a sea bass fishery my entire career.

- At the same time, it can protect the livelihoods of the fishing crews that share these Atlantic waters.

- No fisherman that I've ever met has said, oh, I can't wait to hurt a whale, you know?

The fishermen know the whales are a really important part of the ecosystem.

- That's all for now, and thanks for joining us.

And be sure to check us out on social media.

We'll see you next time on "This American Land."

- For more information about this program, check out our YouTube channel and watch us on PBS Passport.