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CCRM Research: Nontidal Wetlands Research - Frogloggers
One way for determining the habitat function of an area, and it this case
wetlands, is to document the amphibian and bird populations. One method
for examining these populations is to record the different species
present. This can be done by direct field observation of the animal
through sight or sound. Generally some of the best times to observe these
species are either very early in the morning (birds) or in the evening
(amphibians). Since these sites are often very remote it is difficult to
study a sufficient number of sites by direct field observation. One way
that allows observation of a number of sites at the same time is by
setting out automatic sound recording devices. These instruments record
bird and amphibian calls at set times over a number of days without a
human presence.
Sounds generated by human activity (anthropogenic) have been shown to
alter bird and amphibian populations. The low frequency noise from traffic
forces some species of birds to change the frequency of their songs or
leave an area altogether. In some cases, male birds that attract females
through their song cannot be heard and abandoned an area. Obtaining the
'sound signature' of a wetland can shed light on the wetlands level of
disturbance and its ability to provide ecological services that society
values.
Bufo fowleri
Spectrogram of the Fowler’s Toad (Bufo fowleri) call
processed by the software Raven 1.3
(click on spectrogram to listen to the recording)
Froglogger in the field
The Froglogger is composed of a Sennhieser ME62 microphone connected to a Marantz PMD660 digital recorder. The digital recorder and power supply are controlled by a Bedford Technical Froglogger timer/controller. The power supply is a 6V 12 Amp Hr battery.
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