Despite weighing the same as a AAA battery, chickadees have an astonishing ability to endure the severe winter season. The answer to how they do it will give new meaning to the phrase “bird brain.”
Mountain and Black-capped Chickadees are charming songbirds native to Colorado. You can differentiate them by a distinct white line above the eye or the lack thereof. These small black and white birds are so versatile that they can be found from the east coast to the Yukon. Unlike over 400 bird species that travel South along the Central Flyway migration corridor through Colorado, chickadees are here to stay all year round. Even the harsh winters of the Rocky Mountain region are nothing compared to the special adjustments of chickadees.
Mountain Chickadees are charming songbirds native to Colorado with an astonishing adaptation to survive the severe winter season.
Winter poses significant challenges for all living creatures, especially in terms of staying warm and finding food. Avoiding fatal frostbite is achieved by a type of feather we also rely on when the temperatures drop. That’s right, our favorite down jackets rely on the thick insulating down feathers that cover the entire body of a chickadee. Fluffing up these feathers is another method to reduce heat loss by 30%. In humans, we know this phenomenon as “goosebumps.” As night falls, Chickadees enter a state of controlled hypothermia, called torpor, by lowering their body temperature from 108 ºF to 86 ºF. This, combined with slowing their metabolism down, effectively conserves the energy needed to survive severe temperatures. However, staying warm is only one half of the winter battle.
These resilient creatures employ an impressive caching strategy to secure their food supply during the harsh winter months. As winter settles in and temperatures drop, chickadees diligently collect seeds, insects, and other food items. They then hide up to 5,000 morsels in tree bark crevices, under loose bark, or even in the ground in a single day. The success of this caching strategy lies in their ability to recall the locations of these hidden caches when they need a meal. These feathered foragers employ a sophisticated mental map, allowing them to retrieve their hidden treasures with remarkable accuracy even after several months. Researchers have discovered that the hippocampus, a region of the brain associated with memory, grows up to 30% in chickadees during the winter months. The volume of neurogenesis is dependent on the severity of the winter in the area and thus population differences are seen. For that reason, a chickadee in Colorado has fewer neural changes than a chickadee in Alaska. This adaptation enhances their memory and navigational skills, allowing them to find cached food efficiently.
Why can’t they retain a large brain with incredible memory all year long? While this extraordinary neurogenesis is necessary for their winter survival, it is superfluous come spring time. Researchers have discovered that chickadee brains shrink back to their pre-winter size in early spring; however the intricacies of this process still remain a mystery. It is believed that after the memory neuron successfully leads a chickadee to its saved food, it can consciously be deleted from the brain. This brain plasticity is truly the secret to their winter survival.
Chickadees' remarkable winter caching behavior not only highlights the incredible adaptability of these birds but also serves as a source of inspiration for researchers studying memory and cognition. Understanding how chickadees masterfully navigate their winter cache can provide valuable insights into the intricate workings of memory in the animal kingdom, offering lessons that extend beyond the avian realm. In a world filled with marvels, the chickadee's winter caching behavior stands out as a testament to the ingenuity of nature.
Lucy Trosper is a Lead Naturalist at Walking Mountains with a brain a chickadee could only dream of.
