Notes

Slide Show

Outline

1	Eavesdropping on Alarm Calls Art McMorris DVOC April 19, 2007
2	Alarm calls Many species give alarm calls Birds, mammals, etc. Why? Alerts others… Protects one’s own genes Solicits help
3	Black capped Chickadee alarm calls
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6	Playback of recorded calls
7	Acoustic features of “chick-a-dee” calls
8	Chickadees give more “dee” notes in response to smaller predators
9	Versatility of “chick-a-dee” call Warns of perched predator; solicits mobbing behavior Tells level of threat Food call Identity call Individual Flock “All clear” signal What acoustic features carry all this information?
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11	Red-breasted Nuthatches Not closely related to chickadees Similar in Size Habitat Flocking Predators
12	Red-breasted Nuthatches: responses to recorded chickadee calls
13	Why is it important for birds to discriminate between levels of threat? There’s more urgency in chasing out higher-risk predators Conversely, it’s very important not to expend excess time and energy when the risk is lower
14	Conclusions Nuthatches eavesdrop on chickadee calls They recognize which calls are mobbing signals They discriminate between subtle signals in alarm calls, and respond appropriately Clear adaptive value for nuthatches Implications for using chickadee playbacks in bird census studies
15	References