Black-capped Chickadee (Poecile atricapillus)

February 19, 2017 Elise

On a recent trip to Parker River National Wildlife Refuge yesterday, my friend and I saw a number of new-to-me birds, including a Barred Owl (Strix varia) and an American Tree Sparrow (Spizelloides arborea). However, those sightings were often fleeting and from a great distance. The Black-capped Chickadees (Poecile atricapillus), on the other hand, were bold and curious and often perched only a few feet from us to search for food amongst the branches and reeds.

Black-capped Chickadee (Poecile atricapillus) – Photo credit: Brittany Hoffnagle

I mentioned chickadees briefly in my post about bird banding at Welfeet Bay Wildlife Sanctuary, discussing how unlike many other small birds in this area, chickadees are non-migratory, year-round residents. One adaptation that likely helps such a small bird survive the cold winter nights so far north is that Black-capped Chickadees can actually reduce their body temperature by as much as 10 to 12 °C (from their normal temperature of about 42 °C) to conserve energy. This is referred to as torpor, a state of reduced physiological activity and metabolic rate.

Another behavior that helps the Black-capped Chickadee survive less-than-ideal conditions is that they frequent a variety of habitats, increasing the locations they can search for food when it is scarce. At the Parker River National Wildlife Refuge, we noticed them in both forested areas and amongst the reeds of a Phragmites marsh. Black-capped Chickadees forage by hopping between twigs and branches searching for food. They are quite acrobatic and will often hang upside down to reach underside of branches. During the winter, a Black-capped Chickadee’s diet is about half plant-based (i.e. seeds and berries), and half animal-based (i.e. insects, spiders, and sometimes bits of meat from dead animals). This distribution changes in the summer, when there are more insects to eat. Caterpillars, in particular, are a favorite food item. With this shift in diet, plant-matter may be only 10% of the Black-capped Chickadees diet in the summer.