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Observations in Nest Engineering

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Article and photos by FMN Stephen Tzikas

Feature photo:  Eastern Bluebird nest, Box 3. May 1, 2021, Langley Fork Park.

Animals can have fairly skilled abilities, like that of a beaver building a dam, wasps constructing a hive, an octopus maintaining a garden to hide and reinforce its den entrance, or a bird building a nest. Birds can build nests in a variety of areas, urban or rural.

In 2021, I volunteered to become a bluebird monitor at the Langley Fork Park, in McLean, VA. It is one of the great variety of master naturalist programs available to volunteers. I was partial to it primarily because I had a pet parakeet as a child and knew how extremely intelligent and friendly these birds are. In 2022, I became the trail leader.

The Virginia Bluebird Society’s monitoring program offers a great opportunity to see new born birds very close. It’s not just the birds I find interesting, but also their nests. My favorite Bluebird monitoring document is found at this link from the North American Bluebird Society:

http://www.nabluebirdsociety.org/PDF/NABSFactsheetMonitoring.pdf

It is a useful document that discusses the identification of birds, eggs, and nests.

House Wren nest, Box 9, July 16, 2021, Langley Fork Park.

It’s all fascinating and perhaps the most interesting to me, as an engineer, is how nests are made. Each species has a unique nest. One might ask why and how? I haven’t found too much literature on why each type of bird builds a nest the way they do. So I will speculate a bit.   At Langley Fork Park the Tree Swallows and Eastern Bluebirds are the most successful birds inhabiting the boxes, with the Tree Swallows having a slight edge. In 2021, we had one successful House Wren nesting event. While maintaining the bird boxes this Fall, I noticed a mouse built a nest in a birdbox surrounded by overground shrubs, which allowed it to reach the entrance.

Eastern Bluebirds build neat, cup shaped, woven nests of fine grass or pine needles. Tree Swallows

Tree Swallow nest, Box 5, May 21, 2022, Langley Fork Park.

build nests of coarser grass lined with feathers. Their cup is flatter than those of Eastern Bluebirds. House Wrens build haphazard nests of twigs, occasionally lined with feathers. House Wrens pile twigs creating a cavity in which they choose to nest, acting as a barrier between nest and entrance. House Wrens can be fierce competitors for nest sites, but generally speaking, the House Wren, as a species not as competitive as the Eastern Bluebird or Tree Swallow, has a security structure embedded as part of its nest.

Birds can also build unlined eggless “dummy nests” in nearby boxes to reduce competition. Dummy nests are also built by males, perhaps to offer the females some choices on her preferred location and once chosen, can be finalized.

From the Factsheet link I provided, the mouse has a messy nest. Mice usually make their nest from a variety of materials, such as grass, leaves, hair, feathers, shredded bark, moss, cotton, or shredded cloth. My son had a gerbil as a pet. I can say gerbils are not as intelligent as birds. Given this observation of their fellow rodent, and that mice are quite timid and scared, their nests are conducive to hiding. A mouse did not make a quiver when I opened a bluebird box weeks after the end of a season and found a mouse nest. Its nest was built to hide at all costs. Upon emptying the nest the mouse quickly ran away.

House Wren nest, Box 9, side view from 2021 season.

Eastern Bluebirds and Tree Swallows, who are competitive and successful, perhaps have the luxury to build a more comfortable nest given their abilities to defend their turf. The Eastern Bluebird, perhaps being particularly skilled, can find those extra soft grass blades and soft twigs, being quite comfortable for a refined nest for their hatchlings. The Tree Swallow, who includes some coarser twigs, can make up in their selection of cushy feathers to keep their young nestlings comfortable.

If birds were people, we might amusingly attribute the following characters to their work:

  • Eastern Bluebirds – build with “engineering precision”
  • Tree Swallows – build with warmth and comfort
  • House Wrens – build with safety and security

 

Bluebirds at Langley Fork Park Continue to Thrive

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Feature photo: Bluebird nestling residents of Box 6 (May 21, 2022). What are they thinking?

Article and photo by FMN Stephen Tzikas

The 2022 Bluebird box monitoring season at Langley Fork Park in McLean was my second year, and first as its trail leader. The trail leader duties came unexpectedly, but it successfully concluded thanks to the existing and new trail monitors who helped me with this success. Although I wrote an article last year on the extraordinarily successful season at Langley Fork Park, in part due to the cicada bounty, I was pleasantly surprised that this year’s Bluebird fledglings approached very close to the number we had last year.

In 2021 we nurtured 63 total protected birds which included 26 Bluebirds. In 2022 we had 57 total protected birds which included 24 Bluebirds. This can be contrasted to the 5 years prior to that in which Langley Fork Park monitoring succeeded with about 40 protected birds per year which included about 5 Bluebirds a year. Since our efforts are on behalf of the Virginia Bluebird Society and the Bluebirds themselves, having about a 5-fold increase in Bluebirds these past couple years was phenomenal.

As trail leader, I had a closer look at the total 7-year record of data at Langley Fork Park in order to determine if any changes in the location of the Bluebird boxes were necessary to increase the effectiveness of the Bluebird program even further at Langley Fork Park. This data is part of the Nest-Watch database administered by Cornell University. I found the record-keeping in the years prior to 2021 to have some gaps, but this did not detract from the large increases recorded for the Bluebirds at the park. Nonetheless, the gaps were an interesting comparison that should not be ignored for a program’s quality control. Monitoring in prior years were not always on a weekly cadence, and it was not certain if preventive maintenance was rigorous. While I could infer final fledgling counts on what was recorded, these numbers could have been a bit higher and a good maintenance regimen could have made a nest box habitat resilient for an immediate welcoming of a new set of Bluebird parents during critical times for egg laying. This is contrasted to a strict weekly check on the birds in 2021 and 2022, and immediate attention to issues of concerns: wasp nests, ants, predators. For Bluebird monitors, I can’t emphasis enough how important these matters are. Bluebird monitoring trails should have an adequate number of team monitors to keep pace and avoid burdens with scheduling for a trail that has too few monitors.

With this analysis I did have enough data to make some conclusions for future planning. In the past 2 years, 3 of the park’s 10 boxes had successful Bluebird nestlings, while in the entire past 7 years, 6 of the 10 boxes were home to successful Bluebird nesting attempts. Considering that Tree Swallows are also a protected bird and the main successful competitor of the Bluebird boxes, our Bluebird attempts are good.   But can we do better? These are decisions for our trail that may help others in their trail decision-making too.

Before the close of the 2022 season, our team suggested that moving boxes 1, 4, 7, 9 might help the Bluebirds, because currently they had some issues with predators and intense competition.

The data showed that boxes 1, 2, 5, and 9 never had Bluebirds.   We also have the opportunity to add an 11th Bluebird box which will be determined at a later date. While boxes 2 and 5 may never have had Bluebirds, they are in good locations and have other active protected birds nesting here. These will not be relocated for now.

  • Box 1 is in a fairly hidden area. By moving it closer to the parking lot it may get more attention by the Bluebirds.  There is some playground equipment here, but on closer inspection it is for adults to exercise who are not likely to interfere with the box.  The location is more bushy, so it may also attract more House Wrens too.
  • Box 4 has had occasions of broken eggs from intense competition.  Moving it from the corner of the field to a more bushy area closer to some benches could improve it.
  • Box 7 may be too close to a tree with snake predators. Moving to a more bushy area a few feet away may help.
  • Box 9 is in a fairly active area with baseball activity, and relocating it closer to Box 8 may help. The advantage of the new location is that it is slightly less active and has more trees, but it is not necessarily a suggested 100 foot separation from Box 8.

The 2023 season will evaluate these adjustments.

Virginia Bluebird Society Conference, November 11th & 12th

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Friday, November 11 & Saturday, November 12, 2022
6 pm Friday – 3 pm Saturday
Northern Virginia Community College in Woodbridge
2645 College Dr., Woodbridge
Registration on the VBS website in early September
Contact [email protected] for more information

Virginia Bluebird Society be celebrating the 25th anniversary of their founding. Whether you are an experienced bluebird landlord or just beginning, they have breakout sessions both fun and informative planned with you in mind. You need not be a VBS member to attend.

Presenters include VBS’ own Anne Little on Bluebirding 101 and VBS Vice President Doug Rogers providing tips and tricks for the bird photographer. Jessica Ruthenberg, Virginia Department of Wildlife Resource’s Watchable Wildlife Biologist will advise you on creating backyard habitat. Wildlife rehabilitator Maureen Eiger will be joining us and we have two North American Bluebird Society directors providing answers to all your questions.

And while you may not have heard of their Keynote Speaker Julie Zickefoose, you will be “wowed” by her. She is a prolific artist and writer. On her website you can see her artwork, listen to her past lectures, and read her blog. She will be selling copies of her books and prints at the conference. Welcome to Julie Zickefoose.com

Bluebird Monitor Coordinator Sought

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Photo:  J. Quinn

The Virginia Bluebird Society is looking for one or two volunteers to join a small team that works together to fulfill the duties as the Fairfax County Coordinator. The job entails being the County Coordinator contact for some of the trails in the county, sending out reminder emails to trail leaders in the spring, collecting data from trail leaders in the fall, answering questions and providing advice about bluebird trails and monitoring, and helping to connect people who want to monitor with trail leaders. If you enjoy providing training/educational programs, that’s possible as well. Most of the work is computer based, but it can sometimes involve going out to a site. The time involved varies over the course of the year and occasionally/rarely exceeds one hour/week.

Please contact Carmen Bishop with any questions. – [email protected]

FMN CE Hike: Bluebird Box Monitoring — Awesome!

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BB nest feature photo by Barbara J. Saffir

Have you ever wondered what’s inside those white boxes on poles standing in open fields? They are Bluebird boxes paid for and erected by Bluebird Societies to provide habitat for Bluebirds, native cavity nesters. Trained personnel regularly monitor the boxes to record data for scientific research. A Fairfax Master Naturalist group recently explored the inside of 12 of them with Larry Meade, Northern Virginia Bird Club President and volunteer with the Virginia Bluebird Society. I was reminded of the carol The 12 Days of Christmas as Larry carefully opened each “gift” for a peek inside.

Organized by FMN Barbara Saffir, we met at Clark’s Crossing in Vienna on the Washington & Old Dominion Trail. Larry tapped the side of each box first to warn the parent bird of our approach. Their departure from the box was our first clue to which species was inside. The boxes are intended for use by Eastern Bluebirds but the conservation groups don’t mind if they are used by Tree Swallows (TS), Chickadees and other native cavity nesters. Nesting by other species, such as the non-native House Sparrow, is prevented by removing nesting material before it is completed. The opening is too small to allow entry by European Starlings.

Larry then unscrewed the side of the box, lowered it and we’d look inside. What follows is the day’s official report, enhanced by Larry’s astute birding observations and comedic interludes:

TS nest by Julie Ables

Nest 1 – TS nest – 5 eggs
Tidbit: Tree Swallows use feathers to “feather their nests.”

Nest 2 – BB nest – 3 eggs
Tidbits: Bluebirds use pine needles to make their nests. Larry was logging eBird sightings and “birding by ear.” He wryly noted “butterflying by ear” doesn’t work.

Nest 3 – TS nest – 4 babies ready to go
Tidbit: We viewed quickly so parents could return and resume feeding these voracious eaters.

Nest 4 – BB nest – 3 babies
Tidbit: Larry used a mirror so we could see the babies tucked deep in the nest. This is the second brood in this box for the Bluebird pair.

Nest 5 – TS – 4 babies

Nest 6 – TS nest – 5 eggs
Tidbit: Parent was agitated and circling us. We moved on quickly.

Nest 7 – TS nest -4 big babies
Tidbit: Box monitors remove a nest after the babies have fledged so parents can build a new one. Turkey Vultures are known as TVs. What is a pair called? A TV set.

Nest 8 – TS nest – 5 babies

Carolina Chickadees by Marilyn Parks

Nest 9 – Chic nest – 3 Babies
Tidbit:  Carolina Chickadees! Parents use moss to make the nest. Chickadees are native species and left alone.

Nest 10 – empty
Tidbit: In nearby trees we see a juvenile Orchard Oriole! Larry notes that seeing a new bird is like seeing a movie star.  So true!

Nest 11 – TS nest – 3 babies
Tidbit: We discover a nearby mulberry tree and taste some of the berries. No wonder birds love them!

Mulberry photo by Barbara J. Saffir

Nest 13 – BB nest – 5 eggs
Tidbit: The nest is about 3 times as high as the other BB nests we’ve seen.

If you are interested in volunteering to monitor bluebird boxes, contact the Virginia Bluebird Society. Monitoring season runs from the end of April to early August each year. The excitement and joy of opening the boxes will enhance your contributions to citizen science!