Tweeters folks: this frog-logger works with birds too


>From FrogLog (newsletter of the IUCN/SSC Task Force
on Declining Amphibian Populations, June 1995)


Frog-logger: An Automated Recording System

Previously unknown populations of anurans in the U.S. are being detected
with the help of a portable automated recording system. This uses a timer
to automatically activate a tape recorder to log animal vocalizations in
the field. The system, dubbed a "frog-logger," also uses a voice clock to
audibly time-stamp the beginning of each sampling interval. It is self-
contained, portable, and weather-resistant.

Michael Dorcas, a post-doctoral fellow at Savannah River Ecology Lab,
designed the "frog-logger" with help from his father, Eugene Dorcas, an
electrical engineer, and Charles Peterson, his doctoral degree advisory at
Idaho State University. Drs. Dorcas and Peterson have used the system to
monitor populations of western chorus frogs, southwestern toads, and
Pacific chorus frogs in Utah and Idaho. They have also been monitoring
frogs and toads, including the potentially threatened gopher frog, at the
U.S. Dept. of Energy's Savannah River Site.

At least nine other scientists across the country are also using the
automated recording systems to monitor populations of frogs as well as
birds. In a number of cases, these systems have detected species that were
thought to be absent.

In one of the most dramatic cases, Richard Seigel of Southeastern Louisiana
University detected a breeding population of barking tree frogs at the
Merritt Island National Wildlife Refuge, Florida, where the species was
previously known from only a single road-killed specimen, in spite of
19 years of field work.

Dr. Dorcas is now collaborating with Ontario Hydro Technologies in Toronto
to develop computer software that can identify animal vocalizations, to
make it easier and faster to analyze the tapes.

For further information, contact Michael Dorcas, Savannah River Ecology
Lab, Drawer E, Aiken, SC 29802 (e-mail: dorcas at srel.edu)(fax: 803-725-
3309).