голубей отогнать и мозг не спалить
useful_faq — 31.05.2019 Производитель пугала умеряет, что только диапазон от 24,5 -- 45,5 KHzобеспечивает надёжную защиту от летучих крыс, так ли это,
мозги из ушей не потекут?
А вот уважаемый Ph.D. Ornithology Rob Fergus не соглашается с торговцем пугалами:
"Birds, on the other hand, usually hear best between 1-5 kHz, with total hearing between .5 and 8 kHz. There is a huge amount of variation between species. Some songbirds—especially those with high pitched songs—can hear up to about 20 kHz. There are some discrepancies in studies of the upper limits of bird hearing, but in the most recent tests, no birds have been shown to hear frequencies above 20 kHz. Even birds like oilbirds and swiftlets that are known to use sound for echolocation in dark caves only use audible sounds between 1 and 15 kHz. For this reason, ultrasonic devices using frequencies between 15-30 kHz are completely ineffective save for a few songbirds."
И не только он ( поиск по --> pigeons ultrasonic KHz, или --> tauben ultraschall KHz )
Чем гонять голубей?
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