- Hi there, I'm Frank Graff.

Weasels are sneaky and hard to find but they may be in trouble.

How birders are doing important citizen science so researchers can save our feathered friends and stream restoration.

We are repairing ecosystems next on Sci NC.

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Watch this.

Hey, you're a weasel!

[people shouting offscreen] See, see?

Telling someone is a weasel is not good.

It insinuates that people are sneaky, but don't worry, it's all part of the story.

And that describes the weasel in the wild, actually, because scientists can't figure out if the missing weasel is a sign the ecosystem is in trouble.

[curious instrumental music] Meet the weasel.

Mysterious, hard to find, kind of sneaky.

They are all traits that give the word weasel a bad name when it's applied to a person.

- [Roland] I really like weasels and in my career I've caught them a couple times on camera, but not very often.

It's like really lucky and I've seen them in the wild only like twice and so they're kind of mysterious.

- [Jeff] But in the wild, those same traits help the world's smallest carnivore survive.

- The other thing with weasels is they're always like in the nooks and crannies, right?

Their whole body design is about going into a hole after a mouse.

- This is the skull of a long-tailed weasel.

I brought it 'cause it really shows one of the adaptations that the weasel has made in its morphology.

It's the shape of its body to be a pure carnivore and that is elongated head, you know, really sharp teeth really helps it not only let navigate the landscape very quickly, move very quickly.

- And we started to wonder how are they really doing?

Like how is their population doing?

Are they just like so hard to see because they're so sneaky or are they actually rare and even possibly declining?

- [Jeff] Two species of weasel call North Carolina home.

The long-tailed weasel is about eight inches long.

It weighs about an ounce.

It's found throughout the state.

The least weasel, as the name suggests, is a bit smaller.

It's only found in the mountains.

In general, weasels may be small in stature but they play a big role in the ecosystem.

- They help control prey populations such as mice.

You know, kind of rodent populations that maybe folks view as undesirable, well, guess what?

Your weasel can help manage those populations.

The other reasons we should get a better idea of what's going on with the weasel population is if they are in decline, that's probably indicative of other things going wrong in the ecosystem.

[soft music] - [Jeff] And that's the problem.

Scientists don't know how the weasel population is doing.

The data suggests weasels may be in trouble.

- We're seeing some patterns that there are places in the country that used to have a lot of weasel records and now don't seem to have very many.

And one of the things we see is some of the hotter areas in the southeast used to have a lot of long-tailed weasels and now they don't have as much.

So that suggests maybe it's climate change, maybe the temperature has risen too much and it's not good weasel habitat.

In North Carolina here we still have them in the mountains where it's a lot cooler and we have a lot less of them it seems like in the Piedmont coastal plain, so we're thinking it could be climate.

But there's other things going on there, right?

There's also more habitat conversion.

More forest has turned to fields.

- [Jeff] But before researchers can say whether the weasel population is stable, growing or declining, scientists need a baseline of data to start with.

So you could say this story is also about building a better weasel trap.

- The trick is when you don't see something, you don't know is it because it's hard to see or because it's not there?

And so one of the things we're trying to do now is figure out a better way to survey for weasels.

- [Jeff] Scientists are testing specialized camera traps.

- And we open up our Mostela box and we have our camera on one end and our tube on the other.

It's basically a PVC tube that has a opening cut out of it.

And what this Mostela box is doing is it's serving as both a visual attractant because with the leaf litter and this opening, a weasel will hopefully think, oh, this is a nice burrow and maybe there's a mouse inside.

And hopefully what's further gonna attract this weasel to go into this opening is we usually put bait, and while it comes in, it slows down hopefully long enough that we get a great picture to identify it.

- We're gonna subject you to an experiment here just like we do the weasels.

- [Jeff] They are also testing different baits to draw weasels to the traps.

- Sweetmeat predator baits.

- [Jeff] Well, now.

- Give that a good whiff.

- Oh!

[Roland laughs] - Oh, oh, okay.

If I'm a weasel, I'm probably gonna go to that one, I bet.

- There we go.

- [Jeff] It's all so the weasel doesn't weasel out of the research.

This looks like a perfect trap.

Why here?

- Why here is because as I was walking through the woods, again, trying to get into the mindset of what is a weasel looking for, we look for falling branches and trees that weasels like to hop on and travel along.

We look for rock cavities.

Rock cavities not only do weasels use kind of to travel upon, but they're gonna poke into that rock cavity, the various crevices, to see if there's any of their prey species such as mice.

[soft music] - [Roland] We're going to places that we think are good weasel habitat, lots of cover, lots of rocks.

And when we set the cameras, instead of just putting them out on a tree, we're putting out different set lures and different baits to see, okay, which are they gonna hit first?

Which are they gonna spend their most time at?

And then that will become in the future our go-to method for surveying for weasels.

Likely whatever the problems are that are causing weasels to decline if they are declining are probably affecting other species as well.

And so getting to understand the problems that one species is having can help you improve the ecosystem for a lot of different animals.

- Tiny streams like that may not seem that important.

After all, there's not a whole lot of water in it, but those trickles of water end up in rivers and lakes and all that becomes the drinking water that we use.

Producer Rossie Izlar takes us to a pilot project for stream restoration.

- [Rossie] This is what we think rivers should look like, straight lines and deep banks.

But actually, left to their own devices, they look way more chaotic.

They curve and twist and flood their banks and all that chaos is great for animals and for us.

Traditionally we don't allow rivers to run free.

So this creek behind me is an example of something we don't want to see.

It's like really steep banks.

The water just rushes through really quickly.

It doesn't come out and flood the floodplain.

It's just functioning basically like a pipe.

But all that is about to change.

There's a big construction project coming which will hopefully fix five miles of stream in this watershed and transform it into a healthy thriving ecosystem again.

And scientists want to know will it actually work?

To answer that question, we need to know what animals are living here now and what will be here when the project finishes?

- So I'm gonna bait the traps with a little bit of rolled oats, sunflower seeds because the rodents love this.

[seeds clattering] - [Rossie] We're here with Radmila Petric a researcher at UNC Chapel Hill.

She's setting out traps to see what small mammals are living here in the Stinking Quarter Tributary.

It's a network of streams that eventually flow into Jordan Lake, a drinking water reservoir that serves around a million people.

Landowners straightened these streams decades ago using state and federal grants.

The goal was to drain water more quickly from farmland.

While it did create more acreage for farmland, it completely destroyed the ability of this stream to filter water and support wildlife.

The construction crew will completely rebuild this section, adding curves and planting the banks with native trees and herbaceous plants.

This will hopefully slow the water down and allow more time for microbes and plants to break down pollutants and create habitat for wildlife.

This method has been used for decades to fix stream and river ecosystems.

- And one of the things that has been grossly understudied is these mitigation projects, we really don't know how effective they are.

We're looking at mammals, we're looking at birds, reptiles, macro invertebrates, as well as water quality and seeing how this is all changing.

Because we're going to monitor for seven years after the mitigation takes place, we're gonna really look at the long-term effects.

And so this is something that has not been done.

- [Rossie] Projects like this are expensive so it's important to understand how they can work better.

Even down to details like which plants they choose for the project.

- Are we planting enough pollinator species?

Because a lot of the plants I look at have like two or three flowering species and that's really not enough for, you know, pollinators.

We really need to add some diversity to it.

- 37 empty.

- [Rossie] One of the things they look for is the balance of native and invasive species.

More native species generally means a more balanced ecosystem.

For example, we found two native field mice which is actually a good sign.

- Our native species are excellent seed dispersers.

They aerate the soils, they're an important food source for lots of the other animals that we have around here.

And basically it maintains a very healthy balance of an ecosystem.

And look how beautiful their little ears are.

- [Rossie] And we also ran into this species, canis lupus familiaris, AKA, somebody's lost dog, Jake.

- Where are your owners?

- [Rossie] Don't worry.

We called his owners and they came to get him.

- That's a bad place to go.

Come here, love.

Come here, it's okay.

- [Rossie] You can see how much trouble Jake had getting out of the stream, AKA, ditch.

Imagine all the other animals trying to use this space and failing.

- I mean they're steep in that not much can go in and out.

Like if you have salamanders, there's not much opportunity for them to, you know, go out and, you know, breed.

- The team is also collecting wildlife data here on another section of the Stinking Quarter Creek that will eventually be restored.

The biggest issue here is the cows.

[cow moos] Okay, so this is a spot that's gonna need some work.

You can see that like cows are coming through here all the time, stomping on the banks, pooping everywhere.

So it's really pretty down here but it's actually a pretty good example of what we don't wanna see.

The restoration team will fence out the cows and stabilize the banks with native vegetation.

They'll also be creating a wetland here right next to the stream.

This field used to be a wetland until it was drained with these large ditches that run through it.

So the restoration team will plug the ditch and allow the water to stay on the land.

- Wetlands are absolutely fantastic at filtering out a lot of these pollutants that we don't want to have in our clean drinking water.

They're important breeding grounds for so many different animals including amphibians and lots of birds.

Many mammals rely on them and so it's an important foraging ground, for example, bats, which I love, I'm clearly biased.

- I'm really excited about this project.

We'll be checking in for part two to see how the landscape has changed after the restoration happens.

And of course we'll have that long-term data from Olivia and Radmila to tell us how the wildlife is responding to these big changes.

- This is why it's really important to do these monitoring projects, not just like a snapshot of one year but over a longer period of time, so we can truly understand how the mitigation is influencing the entire ecosystem.

- Before you restore something, you need a baseline to understand where you're starting from, where you're measuring from.

Producer Evan Howell shows us how birders are part of a huge citizen science project, helping scientists save our feathered friends.

[birds singing] [birds singing] - Having the patience to get out in a strange place and listen and look and try to find evidence that they actually are breeding there, carrying food, building a nest.

Aha.

Can't talk right now, I got an orchard oriole right up here somewheres.

- [Evan] Erla Beagle is a birder.

She says awareness is what it's all about.

- You're talking, you're not hearing the birds.

Me, I'm hearing a great crested fly catcher, a mockingbird and we had the osprey a few minutes ago.

- [Evan] Beagle is what you might call a professional volunteer.

When she's not teaching computer science at her day job, she was birding and that's a verb up in rural North Carolina but drove down just outside Raleigh Durham Airport to show that there's more to birding than just taking a picture.

- I mean a great day, I get like 40, 45 birds.

If I can confirm three or more, that's great.

It takes time to atlas.

- [Evan] She means the Bird Atlas.

It's a five year project started in 2021 sponsored by the Cornell Ornithology Lab.

The goal of the atlas is to identify and catalog all the birds in the state, including those just passing through, but also help make decisions on how to preserve species.

The lab reports the bird population in the US and Canada has declined by a whopping 3 billion since 1970.

And every time she goes out to bird, Beagle says her own observations lead her to believe it's an emergency hidden in plain sight.

- Where are the meadow larks?

What happened to the horned larks?

Why aren't there more screech owls?

Eastern screech owls?

It used to be a typical thing you'd hear at night, whistling in your neighborhood.

Not anymore.

What's happened to them?

So yeah, we want to get this data while there's still data to get.

- But the ocean used to stretch all the way out here.

- [Evan] Some scientists like avian ecologist Lauren Pfarr spend her days thinking about birds and the reasons for the decline.

She says human contributions to climate change are well known and result in habitat loss, which affects bird health.

- Not only do we have the migrants coming in, we have migrants leaving.

[rapid instrumental music] - [Evan] But she also looks at migratory patterns and how humans can actually change them.

- The biggest thing that I think about is light pollution.

- [Evan] Barr says one little mentioned factor is that birds migrate at night.

She says since they use the stars in the night sky to know where to go, lights below confuse them and disrupt their direction.

- [Lauren] It's becoming a huge major problem in places where we have things like lighted billboards, illuminated buildings that stay on all night.

- [Evan] Pfarr says that coupled with warming temperatures can also affect when they arrive.

She says data show the birds are even beginning to migrate earlier.

- They may be nesting earlier.

These resources that they, you know, seek out, so like insects, their food resources, they might not be readily available at that time that they migrated.

[bird singing] - It's exceedingly difficult and expensive and not desirable to list species as endangered.

We're trying to keep common species common.

- [Evan] So without comprehensive data, recommendations are hard to make.

CC King is with the North Carolina Wildlife Resources Commission.

They're using a grid built in a series of blocks, each representing three square miles of area.

King says in the past two years, data has been steadily coming in thanks to the growing number of volunteers but says more are needed in rural parts of the state.

- 2023 we really started to get in there and you can see the blocks really showing up.

These are the priority blocks where we ask people to focus 'cause we can then, you know, use that as a geological point and then interpolate from there what the other birds in the region are doing.

- The indigo bunting is somewhere.

[bird singing] You write down the birds as you go.

It's the best way.

Now we just got a great blue heron.

All he is doing is habitat.

Well, you know, carrying food, no, that's not gonna help either.

But in the springtime, if that thing was carrying a branch, that's confirming it's gonna bring a branch to a nest, called carrying nesting material.

- [Evan] And the repository for all this data is ebird.org where volunteers record and submit what they've seen, but do it in a very granular way.

King says it's like telling a story of each bird, where they are, what they do, if they have kids, you get the picture.

- So it's multiple maps within one map is what I'm trying to say.

So that's why it's an atlas.

- [Evan] King says the purpose of the Bird Atlas is twofold.

One, to collect data on what birds are here and where they are, but also to help officials guide growth and development.

One resource to help those learn how to do it is the Green Growth Toolbox.

- We work really hard with private landowners to not be a regulatory stop.

So once we have all the data, we're gonna make conservation decisions about where we're gonna develop and where we're gonna encourage people not to.

Right here, for example, this is a riparian corridor.

This is like the highway for the critters.

If we could just leave that, then they can connect from one population of species to another.

That's if they're crawling on the ground, but the birds have the same thing.

They need a way to get through.

Likewise here, if you're gonna develop a thousand acres with houses, the encouragement is plan the green before the gray.

Make sure you have the special places set aside and then put the houses in.

Instead of putting the houses all over everywhere and saying, gosh, it used to be so pretty here, you could keep it and everybody can win.

Here too, you can see this is a corridor.

You keep a couple of these special places and then you keep some land in between so the critters have a place to move and they have a home and you have a home and we all live here together.

That's the point.

[rapid instrumental music] - Okay, you gotta stop birding at some point, but you can't stop birding.

You start Atlas Bird, you see baby birds everywhere.

[bird singing] Chick chuck, chick, chuck, chick, chuck.

- The ash tree is important to the ecosystem and the timber industry.

Sadly, millions of ash trees across North Carolina were killed by the emerald ash borer.

It's an invasive insect, but scientists are testing a new way to save the ash tree.

Producer Rossie Izlar explains.

- [Rossie] We're here with graduate student Courtney Smith to release a species of wasp that technically doesn't belong here.

This is spathius agrili, a wasp that's native to China and I promise that releasing it is actually a good thing.

Here's why.

This grove of ash trees is a very rare site in the eastern US.

Most ash trees here tend to look like this.

Yep, dead.

And it's all the fault of an invasive beetle from Asia, the emerald ash borer, which showed up in the US about 20 years ago.

- And since that happened, we have lost millions, tens of millions, probably hundreds of millions of ash trees to this one tiny insect.

- [Rossi] Yeah, it's kind of pretty but pretty or not, these bugs, which scientists call EAB, have pushed ash trees to the brink of extinction.

They lay their eggs inside ash bark, and when the larvae hatches, it feeds on the same tissues that the tree relies on for nutrients and water.

So the larvae basically cut off the tree's life support.

You can see the tracks they leave behind called galleries.

This patch in Wayne County, North Carolina is only alive because foresters chopped it back before the beetle could fully establish here.

Now Courtney is trying to head off the emerald ash borer again by releasing its old enemy, the wasp.

- This wasp is native to where emerald ash borer is native so it was brought here from the emerald ash borer's range to control it here as well.

- [Rossi] Okay, yes, I know what you're thinking.

Are we playing with fire by releasing more non-native insects?

But this is a time tested strategy of the United States Department of Agriculture.

It's called biocontrol and it relies on using the natural enemies of invasive pests to control them.

We've used this method many times before, lady beetles to eat citrus pests, wasps to eat alfalfa weevils, another wasp to kill mango-eating fruit flies.

The USDA provides wasps for free that have evolved to target a specific species so they won't go after any other insects that we actually care about.

How do the wasps actually control emerald ash borer?

The answer is pretty gruesome.

- They have a very long ovipositor or egg laying device that they can insert into the bark.

So it's long enough to actually go through the bark and attack the emerald ash borer larvae.

- [Rossie] Depending on the species, the wasps lay their babies inside the beetle's eggs or on top of its larvae.

Then the wasp babies feed on the larvae before it can grow up and eat the ash tree.

- It's a little bit like the movie "Alien" where, you know, the parasitoid is inside the host and then it bursts out and kills its host on the way out.

That's exactly what it's like.

- [Rossie] And this has worked really well in some northern states.

But down here in the south, it's been tricky.

The types of wasps we release here actually prefer larvae when they're a little older.

- So it's really tricky to make sure that we know what stage the emerald ash borer is in at what time of year to be able to release them.

- [Rossie] Scientists are just starting to understand these lifecycles and for many ash trees, it's too late.

Biological control is just one tool scientists are trying.

There's also a more subtle tactic, this one centering on the trees, that against all odds, are beating back the beetle.

Here's the dead trees again.

But do you see those patches of green?

Those are what scientists call lingering ash.

Despite their neighbors being long gone, they've managed to survive year after year.

- It definitely gives you a feeling of hope, I think.

Each year you're crossing your fingers, you come back out here and they're still alive and in a field that often can be quite depressing, it helps a lot.

- [Rossie] John and his team think there's probably some genetic resistance to emerald ash borer among these lone survivors, but identifying that genetic resistance is harder than you'd think.

- There's not really a magic gene or anything like that that we know of yet.

It's still being heavily researched.

- [Rossie] If they can identify the genes responsible for saving these trees, they can genetically modify a whole new crop of trees to be resistant to emerald ash borer.

We've used this tactic before too, this time on the American chestnut tree that was decimated by blight.

After almost 30 years of research, scientists developed a blight-resistant American chestnut tree.

And ash trees are also a beloved tree in North America.

They're a crucial member of our forests.

They provide habitat to more than a hundred insects and all the animals that eat those insects.

- When you lose ash, you lose that genetic diversity, not just the tree itself, but everything else with it.

- We have about 258 million ash trees in North Carolina so losing them as a species is a pretty big deal.

- [Rossie] Oh, and did I mention that baseball bats are made of ash?

Yep, it's an all-American tree that's quickly becoming just a memory.

- It's devastating.

Like, seeing the mortality that one small beetle could do is really impactful.

But then as we're doing research, we also see that one surviving tree amongst the more than 32,000 trees that we have here.

And then we see promise for the future.

We see hope, we see, hey, maybe there's something going on here and we have the opportunity to study it and then hopefully eventually establish ash again in our ecosystems.

- And that's it for Sci NC for this week.

If you want more Sci NC, please follow us online.

I'm Frank Graff.

Thanks for watching.

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