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Biology

Eavesdropping on Alarm Calls in Mixed-Species Bird Flocks

Quick fact

Chickadees and titmice can understand each other's alarm calls: a high-severity chickadee mobbing call triggers titmice to mob, while a high-severity titmouse alarm call triggers chickadees to freeze, showing that these cross-species signals carry detailed information about the level of threat.

Why this is interesting

When a titmouse screeches 'danger!', a nearby chickadee may dive for cover—even though it didn't see the hawk. How does a bird know that another species' cry means trouble?