A bluebird sighting was becoming a rarity 35 years ago when a small group of bird lovers created the Bluebird Recovery Program of Minnesota.

Threatened by competition from other tree cavity-dwelling birds and a loss of habitat, the songbird known as the harbinger of happiness was going through a decidedly somber period.

The Bluebird Recovery group, a committee of the Audubon Chapter of Minneapolis, built and hung birdhouses and in its first year reported 22 fledglings that flew the nest.

Thirty-three years later, in 2012, the group of volunteers set a record with more than 23,000 fledglings sighted across the state.

Today, eastern bluebirds can be seen along trails, in parks, on golf courses, on school and corporate campuses and even in cemeteries, thanks to the group's efforts.

The Minnesota Department of Natural Resources credits the recovery program and the DNR's Nongame Wildlife Program with fostering one of the most successful bluebird recovery projects in the nation.

For the most part, program participants aren't scientists, just grass-roots volunteers smitten with the plump birds with blue backs and rust-colored bellies, said Carrol Johnson, the statewide coordinator for the recovery program.

Johnson, a retired 3M maintenance supervisor living in Northfield, started fawning over the bluebird about a dozen years ago after reading a newspaper article and attending a lecture.

"I never even knew there was a need," said Johnson, who now maintains and monitors about 60 bluebird houses in Northfield and on his farm in Fillmore County. He also fields dozens of calls a week from bluebird volunteers across the nation.

People fall hard for the little songbird, he said.

"It happens to a lot of our people. People come to our presentation inquisitive. Some people get really hooked," Johnson said. "They really enjoy the process of seeing the birds building the nest, laying the eggs and hatching."

Monitoring houses is critical. Unmonitored houses can actually hurt bluebirds by attracting nonnative sparrows and increasing their population, Johnson said.

On the watch in Anoka

Volunteers mount, monitor and maintain thousands of bluebird houses.

Retired school principal Jeanne Wilkinson is one of them. At sunrise every Wednesday, she and retired schoolteacher Dick Sherva check on 39 strategically placed bluebird houses in the city of Anoka. Wilkinson and Sherva are both active in the Friends of the Anoka Nature Preserve.

Six years ago, Wilkinson took over the bluebird "trail" first established by another bird lover who had died; she assumed the duties at the request of his widow.

Wilkinson is known by her two grandchildren, ages 2 and 5, as "Nana Bluebird." So far this year, they've counted 55 fledglings, with more on the way.

Wilkinson wears an apron to carry odd items and tools she may need — a stick to dig out an old nest, a plastic sack to bag it.

The Anoka bluebird trail includes birdhouses at two cemeteries, the old state hospital campus, the community garden, the county fairground, local parks and the nature preserve.

"Every week you go out, you never know what you'll find," Wilkinson said.

Occasionally she and Sherva, who drive from house to house, get stopped by curious police officers.

"We are kind of nerdy," Wilkinson explains.

Bluebirds favor manicured grassy areas. Their diet is similar to that of the robin — primarily insects — but instead of hopping along the ground, bluebirds prefer to perch on branches, fences or even tombstones until they spot their food and swoop in.

Wilkinson conscientiously records her findings at each birdhouse each week. She peeks in, looking for new nests, newly laid blue eggs and new hatchlings. The cemetery birdhouses often produced the most babies. The bluebirds are tolerant of human monitoring. Some mothers don't even leave the nest when humans peek in.

Other native cavity-dwelling birds — black-capped chickadees, wrens and swallows — will sometimes claim a house. Wilkinson waits for their eggs to hatch and those babies to fledge before cleaning out the box for a bluebird. Volunteers will remove the nests and eggs of the invasive English House sparrow.

A lot of the job is housekeeping — keeping the houses in good repair and cleaned out. Bluebirds, known for their meticulous, neat nest building, often won't use a box if it's already stuffed with an old, trash-laced nest from another songbird.

Whether to intervene

Some critics say it's not good to tinker with nature's balance. But Wilkinson and Sherva assert that it's human interference that caused bluebird numbers to drop in the first place.

"We the people caused the problem," said state coordinator Johnson.

People introduced the English house sparrow, a bluebird predator, to the eastern United States in the 1800s.

"They are very competitive and very aggressive," Wilkinson said.

People also destroyed bluebird habitat and chopped down dead trees with cavities where bluebirds like to nest.

Now human intervention has brought them back.

"You have to [intervene], without the habitat for them," Wilkinson said. "Making bluebird houses and monitoring them is critical."

Mixed midweek news

On this Wednesday, Wilkinson finds several bluebird nests with pale blue eggs that are warm to the touch. In four houses, she finds families of hatchlings — two bluebird clans, black-capped chickadees and tree swallows.

It's not all good news. One house that last week had warm eggs has been opened and emptied. There is no sign of the nest.

Wilkinson investigates the scene kneeling on the ground, theorizing that the birdhouse is too low and a raccoon may have plundered it.

"You become very protective of your babies and eggs, They are such beautiful birds," Wilkinson said.

Sherva suspects curious children may have disturbed the nest. He recalls as a boy taking aim at birds with his BB gun as adults egged him on.

"I got commended for shooting. I was a good shot. It was just idiotic," Wilkinson said.

Today's bluebird work could be a penance of sort, he said.

In recent weeks, vandals have placed firecrackers in two bluebird houses, roasting the baby birds.

But the mother bird came back and laid new eggs and Wilkinson discovered the hatchlings.

In Dakota County, a group of "bluebird engineers" maintains bluebird houses on Flint Hills Resources property in Rosemount, including 500 acres of restored habitat along the Mississippi River.

Four Flint Hills employees led by senior process engineer Renee Smith volunteer for bluebird duty. So far, they've counted 53 fledglings and another two dozens eggs ready to hatch. They will report their results to the bluebird recovery program this fall.

Smith spends about an hour a week checking the bluebird boxes and doing any necessary maintenance. Gnats, which kill hatchlings, can be a problem, so they spray the boxes with cooking vanilla as a deterrent.

Smith, who has always had an interest in nature and conservation, took over bluebird duties in 2012.

"The are so pretty. It's amazing to see these birds," she said. "It interesting. I like being able to hopefully make a difference."

To learn more about the Bluebird Recovery Program of Minnesota, go to http://bbrp.org/

Shannon Prather • 612-673-4804