by 2021 Outreach Assistant, Jessica Tinholt

I remember the first time I found a snake in a nest box. Looking back, it was probably a plains garter snake with a distinct yellow stripe from tip to tail, but 12-year-old me didn’t care. I sprinted from the fence line back to the road where my grandfather was in our vehicle, clipboard in hand, waiting to write down how many eggs were in the nest. After jumping into the passenger seat, I told him what I had seen: a snake in my nest box!

Technically, the nest boxes belonged to the landowner who put them on her fence line, but Papa and I had been taking care of them for the past few years since her husband passed away. As far as I was concerned, the boxes were mine. I protected those little birds. We cleaned the boxes out in the fall, fixed them up in the spring, and monitored the birds throughout the summer. The data collected from our string of 62 boxes were passed on to the Mountain Bluebird Trails Conservation Society (MBTCS), who are dedicated to studying and conserving the mountain bluebirds. We provided them with species, egg numbers, and hatch dates to contribute to the pool of knowledge surrounding birds in our area.

It wasn’t uncommon to lose a nest. Sometimes an egg would not hatch, or the wind would blow the top of a box open and force the hatchlings out too early. We had lost nests to weather, people, and sparrows, but never a snake.

*Nest box with a single bluebird egg. Photo: Jessica Tinholt.*

My grandfather walked me back to the nest box, which was now empty. No snake, no birds, no eggs. The snake had disappeared into the grass with a full belly. I watched as Papa crossed nest box #14 off the list, and I started to cry. You see, that nest box had been my favourite. It was the perfect spot, sheltered by trembling aspen and tall grass, perched atop a rolling hill that overlooked a meadow with a babbling stream. More importantly, it was the third year in a row that a pair of mountain bluebirds had chosen to nest there. We had other bluebirds, but the majority of our boxes were occupied by tree swallows. Elegant as the swallows may be, the bluebirds were my favourite (and still are).

Papa patted me on the shoulder and said, “That’s the way the cookie crumbles.” He closed the lid of the box and walked back to the car. I followed him, dragging my feet so much that I tripped on barbed wire, and didn’t say a word. We continued on our route and checked the rest of the boxes, all of which had eggs. The last box was occupied by a house sparrow. We cleared out the invasive bird by removing the nest. I never liked destroying the little speckled eggs – it wasn’t their fault that they were a pest – but it is a necessary part of nest inspections in Alberta.

A few weeks later, we came back to check up on our bird boxes. When Papa pulled the car up alongside #14, I did not get out. I told Papa that I did not want to see an empty nest and we should just move on, but he insisted that I go check. If the pair of bluebirds had not returned by now, we would clear the old nest to make space for new birds. So, I grabbed the pair of deerskin gloves and trudged my way up the grassy slope to the nest box. There were no birds in sight, only the caw of a crow in the distance. I struggled with the latch, mustering up the courage to glance inside. At last, I looked. Huddled in the nest, blue as an Alberta sky, were six perfect eggs! Our birds had laid a second clutch of eggs in previous years, but never so soon. I closed my nest box and squealed in excitement as I hopped back to the vehicle where Papa waited. He erased the line he had drawn through #14 and wrote in: 6EGGS,BB.

Why Nest Boxes?

Bluebird Pair With Box - Debbie Jo Webster.jpg

Nest boxes are sprinkled throughout our watershed. You may see them attached to fence posts along the Cowboy Trail (AB Highway 22), power poles, and even trees. According to the MBTCS, there are 2.9 million fewer birds today (in the US and Canada) than in 1970. Theories for this decline include habitat loss, human development, and increased predation. Bird populations are also heavily impacted by adverse weather (made more extreme by climate change), which dictates when food sources are available and the success of their broods.

The implementation of nest boxes is meant to compensate for the loss of nesting sites and vital habitats due to land clearing and development. This is especially important to species like bluebirds, who are cavity nesters and rely on standing dead trees for places to nest. Bluebirds can’t build a nest just anywhere. Thus, nest boxes are perfect for areas that have lost older stands of forest to agriculture and development.

While snakes contribute to the threat of predation, nest boxes are also subject to competition, vandalism, and inclement weather. Native birds aren’t the only cavity nesters that love these boxes; house sparrows, an invasive species to Canada, also take advantage of the prime nesting spots supplied by nest boxes. Sparrows will even attack bluebirds occupying a nest box and push them out before building their nest right on top of the old one. House sparrows are most common near settlements or barnyard settings, and can be avoided by situating nest boxes more remotely. However, if a house sparrow is in a nest box, it must be removed. Other threats include vandals or strong winds that will knock open the lids of nest boxes, leaving the inner box exposed and no longer a cavity suitable for nesting.

Still, most nest boxes lead to great success and many happy birds. The MBTSC alone monitors over 2600 nest boxes across Southern Alberta, many of which are in the headwaters of the Oldman River and our watershed.

How to Get Involved

*Twelve-year-old Jessica taking notes in the backcountry. Photo: Al Tinholt 2011.*

If you love our native birds as much as I do, one way you can contribute to their conservation is by putting up a nest box of your own! If you are anywhere in the Oldman watershed, there is a good chance that bluebirds and tree swallows in your area would love to nest in your backyard.

Nest boxes require specific measurements and placement to attract the birds you wish to house. The MBTCS, as well as other organizations such as the Cornell Lab and Ornithology, provide bountiful information about how to set up a proper nest box. Nest boxes are also an incredible, firsthand way to get your friends and family involved with nature and feel better connected to our watershed.

Some of my fondest childhood memories involve warm summer evenings with my grandfather, driving down those dusty roads and counting how many bluebirds were in our boxes. There is nothing so precious as peeking inside a box to find a nest of baby birds peering back up at you, mouths wide and chirping for food. Those evenings were about more than data collection and monitoring. The time Papa and I committed to our nest boxes was also time we spent together and connected with nature. I loved every second of it… even when there was a snake in the nest box.