The chickadee in the snowbank: A 'canary in the coal mine' for climate change in the Sierra Nevada mountains
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Thursday, January 4, 2024
As we reach the remote research site, I duck under a tarp and open a laptop.
Key Points:
- As we reach the remote research site, I duck under a tarp and open a laptop.
- A chorus of identification numbers are shouted back and forth as fellow behavioral ecologist Vladimir Pravosudov and I program “smart” bird feeders for an upcoming experiment.
- In recent history, intense winters are often followed by drought years here in the Sierra Nevada and in much of the U.S. West.
- Our research shows that a mountain chickadee facing deep snow is, to borrow a cliche, like a canary in a coal mine – its survivability tells us about the challenges ahead.
The extraordinary memory of a chickadee
- Cognition is the processes by which animals acquire, process, store and act on information from their environment.
- Then, they use their specialized spatial memory to retrieve those food caches in the months to come.
- We measure the spatial memory of chickadees using a classic associative learning task but in a very atypical location.
- The setup allows us to measure the spatial memory performance of individual chickadees, because they have to remember which feeder their key enables them to open.
What’s the problem?
- Harpold works to understand variations in climate patterns within forest environments, and one of his field sites lies alongside our chickadee research site.
- The Sierra Nevada and other mountain ranges in western North America have been experiencing more extreme snow years and drought years, amplified by climate change.
- In 2023’s record winter, over 17 feet (5 meters) of snow covered the landscape that our chickadees were using every day.
The cascading harms from too much snow
- And if they do survive the winter, their nesting sites – tree cavities – may be buried under feet of snow in the spring.
- Extreme snow oscillations also affect insects that are critical for feeding chickadee chicks.
- Snow cover is good for overwintering insects in most cases, as it provides an insulating blanket that saves them from dying during those freezing months.
- However, if the snow persists too long into the summer, insects can run out of energy and die before they can emerge, or emerge after chickadees really need them.
- This leads to a decline in chickadee populations in years with worse whiplash – drought followed by high snow on repeat – especially at high elevations.
Lessons for the future
- Our long-term research following these chickadees provides a unique window into the relationships between winter snow, chickadee populations and the biological community around them, such as coniferous forests and insect populations.
- These relationships illustrate that climate change is a more complicated story than just the temperature climb – and that its whiplash and cascading effects can destabilize ecosystems.
Benjamin Sonnenberg receives funding from the National Science Foundation.