'Get off my lawn:' Song sparrows escalate territorial threats
Tuesday, February 12, 2013 - 14:01
in Biology & Nature
Territorial song sparrows use increasingly threatening signals to ward off trespassing rivals. First an early warning that matches the intruder's song, then wing waving – a bird's version of "flipping the bird" – as the dispute heats up, and finally, if all other signals have failed, attack.