A fair identification of a off-the-cuff pseudo factoid Phillip.
However for a bird flying at 15m/sec & uttering a cry in the 800hz
range, the difference between the approaching frequency & the leaving
frequency (30m/sec) is about 65hz. http://en.wikipedia.org/wiki/
Doppler_effect
I am not sure if I can really detect 65hz or 8% change but this is
approximately the difference between G5th & F5th http://
www.phy.mtu.edu/~suits/notefreqs.html
Nevertheless I think I perceive a lower frequency as they depart.
Similarly with overflying Ravens - the last 'aahhhh' always sounds
more mournful than when they are approaching, dont you think?.
Regards, Chris
Chris Charles
0412 911 184
33deg 47'30"S
151deg10'09"E
On 13/02/2010, at 12:07 PM, Peter Shute wrote:
How fast do YTBCs fly? I'm sure I've heard the doppler effect of
relatively slow moving cars, but I think the fact that birds don't
make a continuous sound would make it hard to detect the effect.
Perhaps people are confusing the rise and fall in loudness with
true doppler effect, but either would be equally impressive to hear
from a Lyrebird.
Peter Shute
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