MISSOULA, Mont. —

For more than 30-years, the Owl Research Institute in Charlo has been gathering scientific data on several species of owls.

It's founder and president, Denver Holt, is one of the world's foremost experts on this fascinating, mythical bird.

NBC Montana spent a morning with Denver and his crew as they hiked into country rich with short grass, tall Ponderosa pine trees, and thick brush.

It's home to Long-eared owls.

"We're getting ready to try and capture and band some Long-eared owls here," said Denver. "They have long tufts on the top of their head, which have nothing to do with hearing."

"The ears," he said, "are behind the facial disc as long slits."

The Institute has been gathering as much data as possible on these nocturnal creatures at this same location since 1987.

They study their genetics, migratory patterns, mating system and diet.

They measure stress levels.

"I think long-term monitoring ," said Denver, "is the key."

They start in the winter when the birds are roosting communally.

"We'll trap and band and try to get as many marked as we can," he said.

The birds will start to split up in February or March.

"Some will totally disappear," he said. "Others will start hanging out near old Magpie nests. At least one bird went all the way to Mexico City."

A lot depends on the availability of voles in the area.

Voles are a favorite food source of the owls.

In early spring they have their young.

The voles have been plentiful this year, and that's been good for breeding.

"We've had nests that have fledged, and the owls left the nests and learned to fly weeks ago," said field biologist Beth Mendelsohn. "And we have nests that are still on eggs."

Beth and the crew enter a cool, leafy glen to begin their work.

"If we can recapture the young who hatch here ," she said, "we can get a good idea if they stay in the same area or do they go somewhere else?"

The team prepares an almost invisible net for capture.

Besides Beth and Denver, the crew includes citizen scientist, Dr. Steve Hiro, University of Montana student Madison Henrie and Institute development coordinator Liberty DeGrandpre.

"Liberty just spotted one sitting here above us," said Denver.

Maddie clears brush to make a flight corridor to coax a mother owl to fly into the net.

Once that's completed, Denver, Steve and Liberty step back onto a knoll to watch as Madison and Beth circle around the glen to try to flush the owl out.

There are two unsuccessful attempts.

"She's very skittish," said Beth.

But finally, on the third try, the crew is able to capture the mother owl for banding.

"This is the female we were after," said Denver. "We have a Long-eared owl."

"It's amazing," said Madison as she secured the bird by holding onto its legs firmly so it could be worked safely.

The owl is identifiable because it has an eye injury, probably from the sharp thorns of Hawthorne branches common in the owl's habitat.

The crew has seen injuries like this before.

"We think the injury is related to that," said Steve, "although we have never proven that."

The owl is banded, measured and weighed.

She raised five chicks.

"Dad is here," said Beth. "Dad does pretty much all the feeding while the female is on the eggs."

She checks her brood patch and finds the features are growing back, indicating the chicks don't need to be kept warm anymore.

Steve said the bird's light body mass, wide wing area and feather structure make for a perfect machine.

"It allows them to fly lower, quieter and slower for hunting," he said.

Denver shows us the gray and brown colored plumage.

"It's really an ideal bird to show off camouflage, coloration and patterning,"he said.

In 32-years, Denver Holt an his crew have banded more than 2,000 Long-eared owls and monitored 250 nests.

"We're focused on long-term research and monitoring," he said.

"Our official mission," said Liberty, "is owl conservation through research and education."

"This is certainly the longest-termed study in the United States and Canada on Long-eared owls," said Denver.

He said from 1970 to 2014 in the states and Canada the Long-eared owl population is believed to have declined by 91%.

But this year, he said, theInstitute is seeing record numbers.

"We have a spike in the population," he said. "We'll see where it goes from there."

He said getting a real gauge of owl populations takes years and years.

"We're so programmed for slam-bam short research studies," he said, "but if we want to know how populations do, we have to have long-term monitoring."

"We're only 32-years into it," said Denver, "I think I got another 30-or so in me," he laughed.

"Everything we do is geared towards protecting and understanding these owls," said Liberty as she held the owl that had just been banded. "But we can't do that unless we understand them and what their populations are doing over time."

With that Liberty let go of the owl and it flew into the trees where it came from.

That little owl may be a teacher to us all.

What will she tell us of her adventures?