Mountain Bluebird Nestbox Monitoring
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What is nestbox monitoring.
Nestbox monitoring is a made up of a network of people who volunteer their time to ensure that migratory birds who are cavity nesters (i.e., they make their nests in hollowed out structures like trees) such as mountain bluebirds and tree swallows have suitable habitat available during nesting season. The need for nestboxes became apparent when declining numbers of Mountain Bluebirds were observed in the early 1970’s - this was due to the decline in woodland areas when suburban development accelerated.
Male mountain bluebird. (EXIF data f6.3, 1/250s, 800mm, ISO200)
The Calgary Area Nestbox Monitors Society ( CANMS ) consists of over 100 monitors looking after over 70 trails with over 5000 nestboxes. Their website contains all sorts of interesting and useful resource material about mountain bluebirds and monitoring a nest box trail.
There are minimum requirements for monitoring a nest box trail:
The basic requirement of monitoring is cleaning out nest boxes at the end of the season and making sure they are sturdy and secure for next season (or replacing them as needed). You need to be handy with a screwdriver and paint scraper to clean out the boxes. As many of you know - I love gadgets so Kory bought me a portable electric screwdriver last Christmas and it works a treat
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The next level of monitoring is checking boxes for signs of nesting which occurs early to mid May, followed by checking for eggs (mid May to beginning of June), checking for nestlings/hatchlings (beginning to mid June) and then checking for fledglings (it’s difficult to catch the actual fledging of the birds from the nestbox, however an empty box with lots of fine dust means they have fledged). At this time it’s important to look for any unhatched eggs or dead young in order to provide complete information for CANMS reporting.
An additional administrative duty is completed at the end of the season when you send in recorded stats (number of nests, eggs, fledglings, unhatched eggs, and dead young) to CANMS who then compile an annual report from all of the trails’ data. This information is collated nationally and internationally to understand the health of the mountain bluebird population.
The final level of monitoring is getting qualified to band birds (i.e., attach and identification band to the bird's leg). These are the only people legally allowed to handle the birds (please note: it is illegal to handle adult, young, eggs, nests or feathers of migratory birds in Alberta and there is a hefty fine if you are caught doing so).
I have been monitoring a nest box trail (see this post for how I got started bluebird blog post) for three years now and I can attest to the fact that it is educational and rewarding to be spend time supporting these birds.
CANMS Nestbox Monitoring Workshop
After three years of monitoring, I finally met some of my fellow CANMS members at a nest box monitoring workshop held at the Leighton Art Centre on May 10th. It was really nice to meet other people so passionate about bluebirds and the level of experience and knowledge of the senior society members is awe inspiring.
The view from the Leighton Art Centre. (EXIF data f8, 1/1000s, 120mm, ISO100)
The workshop was organized by society Vice President, Bob Cooper and Jim Critchley did the presentation. It was a really informative afternoon in an amazing setting - if you’re a local and you’ve never been to the Leighton Art Centre, I highly recommend visiting. The centre is located in the foothills with stunning views and art exhibitions as well as a nest box trail.
I attended the workshop with a friend who had not seen a mountain bluebird prior to the workshop. She found the presentation fascinating and now has all sorts of information about these amazing birds - she’s also now seen a few bluebirds and knows what to look for.
Jim getting ready to band an adult female bluebird. (EXIF data f5.6, 1/250s, 120mm, ISO100)
There were a number of children at the workshop and it was so good to see them attentive and just soaking up all the information. When we did the nestbox walk to check on the bluebirds, the kids were following Jim like the pied piper. It was so heartwarming to see them crowded around the boxes and peering inside, being so respectful to the birds and proudly identifying nests as swallow or bluebird based on what they’d learned.
Probably the most scenic locations for a nest box. (EXIF data f7.`1, 1/250s, 120mm, ISO100).
The Leighton Art Centre is home to a nestbox trail with a pathway system to the beautifully decorated boxes that the public can visit. As nesting season is between May and August each year it’s a good time to be able to see mountain bluebirds, but visitors are asked not to open boxes or disturb the nesting birds.
2025 Season
The 2025 season started out a bit slower than previous years due to a late spring and cold temperatures, but we’re fully into the season now with nests, eggs and hatchlings along the 60 box trail that I monitor. We tend to see bluebirds later than other local trails due to being closer to the mountains and being subject to more erratic weather.
A female bluebird with a juicy spider in her beak - ready to return to the nest for feeding time. (EXIF data f6.3, 1/1250s, 800mm, ISO100)
I have found a few dead adult tree swallows in the nestboxes and this is likely due to them returning from their migration with depleted energy reserves and not finding adequate food. Tree swallows hunt insects in the air whereas bluebirds can hunt on the ground as well as in the air which gives them an advantage with earlier returns to nesting areas. If the weather turns cold and flying insects are late emerging then the tree swallows have no food source.
I’ve also seen some vandalism of boxes along the trail with four boxes having their roofs removed and the screws left out so that the lid could fall off the box. Several of these boxes have nestlings in them and this is a very vulnerable stage for them to be exposed to the elements. I was able to reattach the roofs and secure the boxes without any losses to the nestlings, but it is disappointing that someone felt the need to tamper with the boxes - I can only assume they were curious to see the birds.
If you do see nest boxes in your area, I would ask that you don’t disturb them as they are providing a very important function - homes for vulnerable migratory birds between May and August.
Female bluebird showing her brood patch on lower abdomen. (EXIF data f6.3, 1/250s, 800mm, ISO100)
I visited the nestboxes this week and we’re in full swing with bluebird eggs, nestlings and lots of feeding activity going on. I was able to spot several female mountain bluebirds with feathers plucked from their abdomen. They do this once they lay eggs in order to form a brood patch which allows heat from their body to incubate eggs.
Bluebird nestlings through the nestxbox opening. (EXIF data f6.3, 1/250s, 400mm, ISO200)
The tree swallows which return about a month later than the bluebirds are starting to nest and lay eggs and I even saw one nest with 7 eggs.
Typically bluebirds and swallows lay 5 - 6 eggs in a clutch. The young birds are born without feathers and quickly start to grow a fuzzy covering of downy feathers.
It’s not just about bluebirds
Backlit poplar fuzz. (EXIF data f5.6, 1/250s, 840mm, ISO100, EV-1.0)
I find that bluebird monitoring provides me with a great activity that allows me to see all sorts of other wildlife and nature. It’s quite meditative to spend time in nature as it takes me about 4 hours to complete the run.
I’ve seen such wondrous sights this year like the backlit poplar fuzz that reminded me of candy floss machines.
Views of the Rocky Mountains along my trail. (EXIF data f5.6, 1/250s, 120mm, ISO100)
I get to see beautiful sunrises and the Rocky Mountains in all their glory - my trail runs north of Cochrane and to the west with magnificent view of the mountains in certain locations along the trail.
I have spotted great grey owls, hawks and hawk owls along the trail as well as grebes on nests, Wilson’s snipes and a number of other birds.
Wilson’s snipe getting ready to take off. (EXIF data f6.3, 1/1250s, 800mm, ISO100).
Monitoring with a buddy is always fun
Treat time for Roxy. (EXIF data iPhone)
With the house renovations in full swing and demolition occurring this week, we’ve had to make sure that Roxy is ok and not overly disturbed by the noise. She’s been spending time in the camper van, but this week she came for a car ride with me to do the bluebird run. She makes an excellent co-pilot and is happy looking out the window at all the bird activity.
There was no time for on this monitoring trip, but a hard working kitty deserves a treat for all her great support.
We’ve trained Roxy to not go after birds as cats left to roam free hunt and kill significant numbers of birds each year. Knowing what a tough time these birds have migrating and finding suitable nesting spots, we like to make sure we do our part to keep them safe from harm.
Do you have a particular nature related hobby or do you volunteer in a way that helps birds or animals? I’d love to hear about it in the comments below or drop me message directly by clicking on the Connect With Me button.
image of Roxy
Male mountain bluebird perched on a wire fence. (EXIF data f6.3, 1/500s, 800mm, ISO200)
I hope you’ll come back soon, share a cuppa, relax and enjoy more of my musings.
