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Banded avians offer insight into bluebird behavior

Nestwatchers collect data on region’s mountain bluebirds.

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Banded avians offer insight into bluebird behavior

Jackson Hole, WY News

They knew Box 16 was home to baby bluebirds. First-year nest box volunteers Patti Roser and Andrew Langford, who were charged with the care of Boxes 14 though 23, couldn’t wait to peek in.

To be honest, they’d been peering in on the nestlings for weeks, a job they were awarded when coming onto the Mountain Bluebird Nestbox Trail Project, a monitoring endeavor that tracks when the beloved birds arrive in Jackson Hole, when they begin nesting, when the first hatchlings punch out of their blue shells.

Chuck Schneebeck started the trail in 2003, installing a string of wooden boxes along the National Elk Refuge fence. It has since grown to include 112 boxes in Jackson Hole and another 35 in the Dubois area.

The project has also since expanded to include banding, which adds more data to the growing pile of information collected on the region’s resident bluebirds. In the past two years the nonprofit has hired a small team of scientists to come in and band the babies, a point of data that will allow the organization, citizen scientists and the United States Geological Survey Bird Banding Laboratory to know if the bird is spotted again.

Needless to say, Roser and Langford were excited to see “their” babies be banded. They, alongside 10 other full-time volunteers and five subs, had been checking on the boxes all spring.

Box 16 is nestled behind a small berm, blocking its sight from the bike path and Highway 26/89/191. In the field, a female bluebird flew silently above the grass, glancing down occasionally, hunting.

“They’re the only bluebird that hovers,” lead bird bander Katelyn Maley said June 10, a banding day. “We’ll wait a minute.”

The female, less flashy than her male counterpart, as is common in the avian world, delivered the midmorning meal, a caterpillar, to her chirping chicks, then flew out of the box to keep a close eye on the encroaching visitors.

Bluebird banding

A female bluebird carries a worm into a nest box after her nestlings were banded. To reduce stress on adult birds, the banding crew removes only a few babies at a time, avoiding the nest ever being left completely empty.

Maley walked slowly toward the box, lifted the lid and removed two of the four hatchings. She never takes them all at once, she said, a move that’s intended to relieve some stress on the watchful parents. The adults don’t dive-bomb the group as other breeds are known to do, but “you’ll hear the male clack his bill,” Maley said, and the female hops between the wooden poles and the wire fence.

“They definitely have defensive behavior,” Maley said as she carried the babies over to a small scientific station that she and Max Frankenberry, assistant bird bander, set up in the field.

“Isn’t that just the cutest thing you ever saw?” Roser said of the hatchings, their heads covered in downy plumage, their primary flight feathers just coming in.

It’s hard to imagine the nestlings, shy of 2 weeks old, will be full grown by the time they fledge in just a few weeks.

“Be good to my babies,” Roser said as Maley and Frankenberry started to examine the birds.

The banding

The first bird is noted as a female, determined by the color of her primary feathers. Brilliant blue feathers signal a male, more muted colors — paler blue or even aqua — means female. The hatchling is held between her forefingers and gently braced with her thumb. The once-over includes four bands placed on the legs — an official USGS band that will be logged, and three colored bands to allow birders to individually identify the bird, should she be spotted once she fledges

All birds in the 2018 cohort receive peach bands, which are plastic craft beads that happen to be the perfect size for mountain bluebirds. On her right leg, a peach bead and a silver band; on her left, a red bead above a yellow one.

The bird weighed in at 30.3 grams, a measurement taken by swiftly tipping the bird upside down into a small pill vial balanced atop of a scale.

“They don’t look stressed; they just look angry,” Maley said with a smile.

Bluebird banding

The color of the primary feathers indicate the sex of the bird, though Maley admits it can be a tough call when the birds are this young. Most of the birds banded this season were female, she said.

Their downy heads tend to lend themselves to that expression. A few comments are made about the babies looking like “angry old men.”

Her wings are examined, her tarsus — a bone in her lower leg — is measured, a metric that indicates the bird’s size.

It’s believed these birds will migrate to Mexico — “We don’t know where this population will end up exactly,” Maley said — but they’ll certainly fly south once the snow starts to fall. Probably even before. Around this time of year, birders start to see mountain bluebirds, among other species, flock up, a preparatory move that comes before the big flight.

The first year, Maley said, “is definitely the most dangerous year of their life.”

After examining the first bird and a few others, Maley changes her mind. Maybe she isn’t a she. The bird’s sex is changed in the log to a U, for unknown.

“As we went through the season, we got more confident as we looked at more birds,” Maley said in an interview with the News&Guide last week. “Most of the birds that we looked at this season were females.”

Keeping a watchful eye

So far, a few of the birds that were banded last year — all born in 2017 — sport a green band. “Box 90,” the name given to the bird who inhabited No. 90, was also spotted a few times this summer, a notable bird being the only adult opportunistically banded thus far.

Box 90 has a particularly tragic story — she was easily caught in 2017, the result of a bowfly larvae infection in her nest that killed a few of her nestlings and weakened the adult bird.

“Unless it’s a bad infestation, usually the birds can preen off or recharge their blood supply quickly enough that it doesn’t affect them too detrimentally,” Maley said.

Volunteers and staff typically don’t intercede, but in this case, they intervened. The dead babies and the infected nest were removed and replaced with fresh material and sage. Box 90 regained her strength, and the remaining birds flew the coop.

Bluebird banding

Bluebirds and tree swallows (eggs seen here) are both cavity-nesting birds, competing to build their homes. But they can also peacefully cohabitate, as has been seen when boxes are placed side by side.

Box 90 returned again in the spring to her namesake nestbox, producing a clutch of five eggs. But when the team went out to band the birds, the babies were gone and the nest disturbed.

“We suspect it was a mink, based off of what we were seeing in the boxes,” Maley said.

Box 90 herself hasn’t been spotted since.

“Sometimes it’s pretty depressing to go out,” Maley said. “Sometimes they get the adults, too.”

It’s hard not to become attached. Susan Hill, a volunteer who oversees three boxes near Crowheart, said she’s never been able to keep an emotional distance from the birds. One of her first clutches, born in 2017, was the target of a bull snake that had slithered its way up the box pole and into the nest.

The adults circled the box, distressed, she said. Inside were six hatchlings, possibly old enough to fledge.

The petite woman, who spotted the scene “from a distance because you’re not supposed to get too close,” grabbed a 2-by-4 and beat the snake from the box. But it was too late — none of the babies survived the trauma.

“You get very protective. You’re looking at them every day,” she said. “It was hard to lose them.”

Bluebird banding

Volunteer Patti Roser photographs a nest while tracking mountain bluebird nestlings June 10 near the National Elk Refuge.

This year she installed sheet metal around the box poles to prevent creatures from crawling into the nest. A family of six fledged from one of her nests, she said.

“A lot of things happen to little birds. It’s rough out there. Every success we have is a big deal,” she said.

Citizen science in action

Though somewhat informally, the Jackson Hole community has been contributing data on its mountain bluebirds to NestWatch, a program through the Cornell Lab of Ornithology since at least 2001, project leader Robyn Bailey said.

While the project collects data across North America (mostly in the U.S.) through 2,500 “nest watchers,” it is somewhat rare to have data for a species dating back several decades, Bailey said.

“You have to collect data to answer the specific questions you have,” said Bailey, who is also a certified wildlife biologist.

NestWatch has existed in some form since the ’60s, when it was called the North American Nest Card Program. Sometime in the ’80s and ’ 90s the name changed to the Birdhouse Network, and then again to NestWatch in 2008, a nod to the collection of all birds, even those that don’t nest in boxes, Bailey said.

Name aside, however, the program itself hasn’t changed much. It’s a small offshoot of the Cornell lab, which tracks bird data from all over the world.

Locally, citizen scientists have been logging nesting data on bluebirds and the songbirds that frequently compete for the same nesting spaces — house wrens and tree swallows. This year two boxes were added to the line of boxes to possibly provide a spot for symbiosis.

Literature has shown, Maley said, that tree sparrows are slightly more aggressive than mountain bluebirds and may be more assertive when it comes to setting up shop. However, if boxes are placed close to one another — too close for two pairs of tree swallows to breed, for example — one box may become home to a tree swallow and the other may be left for a mountain bluebird. Everybody gets a place to lay their eggs, and the bluebirds reap the benefits of having a bird next door with a little extra muscle.

Volunteers didn’t see this action this year, per se — tree swallows were spotted in the boxes and data was collected on the birds, though the hatchlings were not banded. But it’s only the first year of the trial.

Bluebird banding

Hatchlings are banded between 12 and 15 days, a little later than recommended for Eastern and Western bluebirds. Mountain bluebirds are full size around 18 to 21 days.

Another adjustment that came from field experience, Maley said, was a change in the banding dates. While the literature — which is mostly on Eastern and Western bluebirds and extrapolated to apply to mountain bluebirds — has suggested bluebirds should be banded between 6 and 11 days, Allison Swan, who banded the first birds for the Mountain Bluebird Nestbox Program in 2017, found she could achieve a better fit between 12 and 15 days. They are full-size birds between 18 and 21 days.

Knowing when to band, exactly, especially when overseeing dozens of boxes, falls heavily on volunteers. Which is what makes the program so unique for the community.

“The neat thing about nesting data is anybody can do it,” Bailey said. “That’s why we’re able to ask people all around the country to peek in their nest, whether it’s a mountain bluebird nestbox or a robin’s nest on your front porch.”

The banding, which is tracked through the USGS and not NestWatch, is also an important marker when it comes to studying bird behavior, she said.

“You can’t go into depths about individual bird behavior unless you can tell them apart,” she said.

This year Maley and Frankenberry banded 72 nestlings, down from last year’s number of 98 nestlings and the one adult.

“Optimistically,” Maley estimated about 50 percent of the birds survive the first year.

“That first year is tough,” Maley said. “You have to make it out of the nest. Once you’re out of the nest, you have to figure out how to survive. Then from there you have to learn to migrate.”

But they have seen them come back. In addition to Box 90, Box 37 was also a return bird, a bird that had been banded in 2017 and returned to nest in 2018.

Every bird spotted — be it a blue egg or a blue flash from the sky — is celebrated by staff and volunteers. Unlike house sparrows, a bird romanticized in Shakespearean plays and brought to the U.S., where they became an invasive species, bluebirds are “kind of the darling of the bird world,” Bailey said.

“They get a lot of play, and we love them,” she said. “We have a lot of data on bluebirds, which is great because the more data you have, the more questions you can ask. Nobody reports pigeons.”

The bluebirds serve as Jackson’s reverse of the canary in the coal mine, the community’s sign of impending spring.

“You see the flashes of blue on the landscape and it means spring is here,” Jackson Hole Wildlife Foundation Executive Director Jon Mobeck said.

“They’re the sky,” volunteer Andrea Billingsley said. “They’re absolutely beautiful. These are just sweet, beautiful birds to look at.”

As a note to readers: Outside of trained volunteers, the Jackson Hole Wildlife Foundation staff requests that the boxes, primarily seen along the fence line of the National Elk Refuge, be left undisturbed. If you’re interested in learning more about the project or volunteering, visit JHWildlife.org.

Bluebird banding

A bluebird perches June 10 near the National Elk Refuge. The Jackson Hole Wildlife Foundation Mountain Bluebird Nestbox Trail Project aims to mitigate a loss of habitat for cavity-nesting birds.

Contact Melissa Cassutt at 732-7076, valley@jhnewsandguide.com or @JHNGvalley.

Deputy Editor

Melissa Cassutt’s job should come with a badge. Regrettably, it does not. She oversees Valley, Scene and special projects. She also writes features, mostly about people but often dogs. Send story tips and pet pictures.

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