Climate change turned my nest boxes to help birds into deadly heat traps

This First Person article is by Melissa Hafting who is an avid birder from Richmond, B.C. This column was originally published in June 2022. For more information about CBC's First Person stories, please see the FAQ.

Swallows are an iconic bird of summer across Canada. They swoop and dash gracefully over water showing off magnificent colours akin to bright arrow beams of light. 

My late mother and I loved to watch them skimming the water surface to drink. Their reflections sparkled and lit up the water in ways that made my mother cry out with joy. She was thrilled by all swallows but loved tree swallows the most. She saw them the most frequently, and were easily identifiable with their brilliant blue backs and white bellies. 

Sadly, swallow populations are declining in Canada for many reasons, including a lack of natural nesting cavities, pesticide use and climate change. The warming temperatures can impact many birds by making them return north to their breeding grounds too early. When they do so, they can find there is not enough food to support nestlings. 

In 2020, I petitioned my hometown of Richmond, B.C., to build nest boxes for tree swallows. The city agreed and we installed boxes in three parks. Tree swallows were not nesting in two of them before the program started but they ended up successfully nesting in all three parks. I personally monitored, collected and recorded data about each nest as a volunteer for the city. I also cleaned out the nest boxes at the end of the season.

As I showed my mom my nest boxes, she loved to listen to the swallows chattering by their boxes and watch them fly as they collected food for their young. She was fascinated as they swooped right over our heads.

In June 2021 to the end of July, B.C. experienced a record-breaking heat dome. Daily temperatures soared past 40 C in the Lower Mainland. Millions of sea creatures and thousands of livestock died in the province.

During this time, several swallow nestlings died and the city and I attribute it to the sustained intense heat wave. The boxes I designed were predator-proof and protected the chicks from the rainy cold weather that is more typical of a coastal Vancouver spring. After consulting with an ornithologist, we decided not to place ventilation holes to avoid the chicks from getting wet from the rain, which could then lead to hypothermia or death. 

In the sustained heat, however, the nest boxes became tiny hot boxes that cooked the young swallows alive. Since the chicks were too young to fly, they couldn't escape the boxes. Some were so young, they had not even opened their eyes yet. Some of their tiny bodies looked like leather. I held the tiny, limp bodies in my hand and cried. 

The helpless parents couldn't help their young either. It pains me to think how distressing it was for them. These swallows invest so much time and energy into raising their young. They feed up to 7,000 insects a day to the begging nestlings, something that starts as soon as they hatch until they fledge. 

When the fledglings hatch, they have poor thermoregulation for at least seven days. They need the female to brood them to stay warm. During the heat wave, having her warm body on top of them — and having feathers she carefully selected to keep them warm surrounding them in their cup nests — was a literal death sentence for the chicks. They were loved to death in the intense heat.

When I thought about it all — the wasted effort of the parents, the helpless chicks — it broke my heart. Losing even one clutch is devastating. These swallows are vital to our ecosystem. They aren't just beautiful to look at; they also reduce the number of bugs, such as mosquitoes, that can carry human disease.

In Canada, we are at the northern limits of their range, and second broods or clutches are uncommon. Luckily, in 2021, a couple of the swallow pairs had second successful broods in the nest boxes I monitored and this gave me hope.

I watched these new clutches that were born late in the season towards the end of July successfully fledge and fly away from the nest. I felt like a proud mom. 

At that moment, I was reminded of my mother who I lost last Christmas Eve. She loved me so much and worked hard to raise me to be the woman I am today. She was extremely supportive and encouraging of my love of birding. 

I will always treasure the time we got to share watching these beautiful birds together. I think of her whenever I am with these swallows. They are bright lights that help me to maintain a special connection to her through memories, even if she is no longer physically with me.

It's now a new season and the project is off to a successful start for another year. I am hoping against all hope that there will be no more heat waves this year. In spite of projections for the climate, I'm determined to continue this work. The birds' resiliency inspires me to keep at it. If they won't quit in spite of a warming planet, neither will I.

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Our planet is changing. So is our journalism. This story is part of a CBC News initiative entitled "Our Changing Planet" to show and explain the effects of climate change. Keep up with the latest news on our Climate and Environment page.