200
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mean no. of birds, before |
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mean no. of birds, after |
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mean no. of calls/bird/2 min, before (x 1000) |
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mean no. of calls/bird/2 min, after (x 1000) |
A.M.
P.M.
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250 200 150 100 50 0 |
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| 5/8/90 | 5/9/90 | 5/24/90 A.M. |
5/24/90 P.M. |
5/27/90 | 5/29/90 | 5/30/90 | 6/15/90 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
When insects are flushed by colonial breeding cliff
swallows,
the birds emit "squeak" calls.
These calls alert conspecifics to the new food patch, additional birds may help track an insect swarm.