Occasionally, there are sudden movements, or interruptions, of young in the fall and early winter. Diet Black-capped Chickadees glean their prey from foliage and tree bark. Their diet consists of insects, caterpillars, snails, and spiders. In the winter, they eat berries and seeds that they hide in crevices of bark and under leaves. Similar Species Chickadees Pair Formation and Territoriality Black-capped Chickadees are monogamous, and their pair bonds last for several years.
Most birds establish pair bonds in late fall when flocks form.
Nevertheless, some birds die during the winter, and many birds must find new mates in the spring. Pairs establish and defend a territo- ry, remaining on or near their territory for the rest of their lives. The onset of breeding, however, can be influenced by factors such as weather, food supply, and the condition of the breeding female. They also nest in natural cavities, abandoned woodpecker holes, and nest boxes. Excavation of the nest cavity can take 7 to 10 days.