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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.

toad with microphone

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)

spectrogram of Fowler's toad


Froglogger in the field

froglogger detail

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.