Acoustic Detection of an Unknown Bat Species in Okinawa

Abstract

Pipistrelles of the genus Hypsugo are among the rarest bats in Japan, known from a handful of records. In June 2018, a sequence of echolocation calls apparently by a bat of this genus was recorded by an automatic ultrasound recorder on the island of Okinawa. The calls closely resemble H. pulveratus, a Chinese species never before recorded in Japan, and H. alaschanicus, a very rare species in Japan. They also resemble calls of Hypsugo sp. bats from a small population recently discovered on nearby Amami-Oshima island. The extreme rarity in our recordings, combined with lack of detection in Okinawa by other surveys, suggests that the individual was a vagrant. However, given the cryptic nature of the species on Amami, it remains possible that there is a small and likely endangered resident population, underlining the need for further bat surveys on Okinawa and other Nansei Islands.

Impacts on Bats by a Supertyphoon vs. Ordinary Typhoons along a Habitat Urbanization Gradient

“…Seven species of echolocating bats have been recorded in Okinawa. All of them have easily distinguishable vocalizations [15,16] . Their natural history on Okinawa has been poorly studied, even though most of them are endemic to the Ryukyus and of conservation concern [17] .…”

“…Yambaru myotis (Myotis yanbarensis), birdlike noctule (Nyctalus aviator), and an unknown species tentatively identified as Chinese pipistrelle (Hypsugo pulveratus) [15] , were recorded in our long-term study sites only twice, six times, and once, respectively (each species at just one site), and were excluded from the analysis due to this paucity of data.…”