140: Black-capped chickadees and Mountain chickadees
I’m sitting here on the fifth day of March watching chubby, adorable little birds flit around my birdfeeder, and most of them are black-capped chickadees. I’m not quite high enough elevation to see mountain chickadees, the other species of chickadee that lives in Colorado. These are passerine (perching) songbirds who do not migrate and live throughout the northern half of North America. Today they are devouring my sunflower seeds and flying away to store them in crevices; they are famous for their remarkable spatial memory that allows them to remember the location of their seed caches for almost a month. They are also famous for being able to survive very cold temperatures by lowering their own internal body temperature to conserve energy; inducing torpor is rare among birds.
Black-capped chickadees have incredibly complex vocalizations that they use to communicate predatory threats and foraging locations to flock members when they are in dense vegetation and cannot necessarily see each other. The Wikipedia section on this is very informative and I don’t want to quote the whole thing! The more “dee-dee-dees” you hear from them, the higher the threat level they are attempting to communicate. Other species of birds nearby also respond to chickadee warnings.
Mountain chickadees live – you guessed it – in the mountains. They are remarkable birds, living year round in some incredibly harsh conditions. If you get a chance to ski at Loveland, I recommend taking the ranger-guided National Forest tour where they will talk quite a bit about how the mountain chickadees who live there survive the winter. One way is to make their nests in cavities in trees – those already excavated by other birds such as nuthatches or natural forces – where the interior temperature can be 12-15 degrees Celsius warmer than the outside, and where they are protected from predators like crows. As adults, these birds are monogamous, and tend to live within a very small boundary – just around a square mile.