On 17/05/2007, at 2:39 PM, Evan Beaver wrote:
Do any birds use Echolocation or have ridiculously high frequency
hearing?
Most swiftlets (including the White-rumped Swiftlet in Qld)
echolocate as does the Oil Bird of Northern South America.
The swiftlets & the Oilbirds only use their ability (8-14KHz) to
navigate to and from food supplies. Unlike bats their acuity is not
accurate enough to locate food or any other items smaller than about
7mm. Qld birds rarely fly after dark - so use visual cues, but birds
in NG, Cook Islands, and Fiji, at least - do lots of flying after
dark and so depend on echolocation.
Because the swiftlet calls are audible to us it was great fun sitting
near the cave entrance on Atiu Island in the Cooks, after dark and
listening to the birds navigating around the tree trunks and bushes
below the canopy, then dive past us into the cave and then wind
around the cave passages to their nest and roost sites.
Hopefully wind turbines would not interfere with these frequencies or
if they do that they will not be used on such small islands where the
whole swiftlet population would be at risk.
Cheers
Mike Tarburton
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