Abstract
An acoustical bat use survey was conducted at the NWTC from July 6, 2010 to November 7, 2010, using a passive acoustical method with AnaBat Systems Bat Detectors (Titley Electronics). The purpose of this survey was to obtain information about use by bats within the Project area.
All data were collected from one bat detector was mounted on a fence post within the conservation easement in the northwest portion of the site. Bat activity was determined by the number of bat passes (number of echolocation calls recorded with ≥ 2 chirps) per detector night. Species composition, temporal distribution (by month), and peak activity levels were analyzed.
A total of 12,425 bat passes was recorded during the survey period for an index of activity of 99.40 bat passes per detector night. Of the 12,425 total bat passes, 8,772 passes could be identified to species (70.18 identified bat passes per detector night).
Species identified included big brown bat, eastern red bat, fringed myotis, hoary bat, silver-haired bat, and Myotis bat group (which may include western small-footed myotis, western long-eared myotis, little brown myotis, and long-legged myotis).
Most bats were detected in July (3,952 total bat passes) and August (5,058 total bat passes). The Myotis bat group was most the most frequently detected (4,373 identified bat passes).
There were no peaks of activity during the monitoring period, but rather constant fluctuation.
No Federally- or state-listed threatened, endangered, or candidate species or species of special concern were identified during surveys (USFWS 2010, CDOW 2010).