With the return of colder weather, the birds now visiting your feeders are primarily residents who will stay with you throughout the winter. Many wintering birds gather into stable flocks which move and forage together, and their complex social interactions and vocalizations allow them to send up an alarm, stay in touch, or signal the presence of food. The chickadee-dee call, which gives the Black-capped Chickadee its name, is a great example of birds using call notes to warn neighbors of predators or other dangers.
Understanding how an individual bird reacts to these warning calls was the focus of a recent study which teased apart whether an individual responded more strongly to what it experienced itself (personal information gained by seeing a mounted predator), what it learned from other birds (social information learned from hearing recordings of chickadee mobbing calls), or a combination of the two. They found that instead of reacting very differently to personal or social cues, an individual Black-capped Chickadee showed a consistent level of caution: if an individual bird reacted strongly to one kind of warning, it reacted strongly to the others as well. The authors noted that the social + personal information cue produced the largest differences between individual birds.