A glimpse into the foraging and movement behavior of Nyctalus aviator: a complementary study by acoustic recording and GPS tracking

Species of open-space bats that are relatively large, such as bats from
the genus Nyctalus, are considered as high-risk species for collisions
with wind turbines. However, important information on their behavior and
movement ecology, such as the locations and altitudes at which they
forage, is still fragmentary, while crucial for their conservation in
light of the increasing threat posed by progressing wind turbine
construction. We adopted two different methods of microphone array
recordings and GPS-tracking capturing data from different spatio-temporal
scales in order to gain a complementary understanding of the echolocation
and movement ecology of Nyctalus aviator, the largest open-space bat in
Japan. Based on microphone-array recordings, we found that echolocation
calls during natural foraging are adapted for fast-flight in open space
optimal for aerial-hawing. In addition, we attached a GPS tag that can
simultaneously monitor feeding buzz occurrence and confirmed that foraging
occurred at 300 m altitude and that the flight altitude in mountainous
areas is consistent with the turbine conflict zone. Thus, our acoustic GPS
survey clearly identified N. aviator as a high-risk species in Japan.