To effectively manage a threatened species, it is essential to have current information on its abundance, how many populations remain and where, and whether its numbers are declining and why. This kind of knowledge can only come from repeated surveys or monitoring. Although the idea of counting how many animals there are in an area sounds simple, it can be surprisingly difficult to do, particularly for rare or “cryptic” fauna.
The Ground Parrot (Pezoporus wallicus) is one such cryptic species, and one of only three ground-dwelling parrots in the world. It lives in highly flammable heaths and has declined in abundance and extent throughout its range. It is threatened in New South Wales and the Western Australian sub-species is critically endangered.
Outside the three core populations in New South Wales there is only patchy knowledge of its current distribution and abundance. Because it lives in dense vegetation, rarely flies and is hard to see, and usually only calls before dawn and after sunset, it is difficult to detect using the usual bird survey methods.
One of the ways to detect cryptic species is to listen for their calls. However, for species that only call unpredictably or at night, or which live in remote areas, even this can be difficult. In addition, animal calling activity can vary greatly from day to day or time to time, meaning that what you hear on any particular day may not be typical.
An innovative new method is automated digital field recorders used in conjunction with call recognition software. Digital field recorders are self-powered, independent, weather-proof units that can be put on site to collect continuous data for days or weeks (or more) – maximising the chances of “sampling” days when many individuals are calling. The affordability of some of the units now available means that it is possible to deploy many units simultaneously – enabling monitoring of many populations and species at once.
Although traditional analogue recording of bird calls has been in use for decades, and bat call recording and recognition used in Australia since the 1990s, it is only in the last few years that call-recognition software for other species has become available. Such software allows days of recordings to be analysed in minutes by a computer.
This research project is trialling the use of a recently available compact and affordable digital field recorder, the “Song Meter”, and several new call recognition programs, to assess the current status and distribution of the Ground Parrot in New South Wales. It is also developing the technology to use an array of recorders to assess the exact location of calling animals, and carrying out trials of the methods for other cryptic threatened fauna.
One of the reasons why better information on the abundance and location of the populations of the Ground Parrot is critical is because they are sensitive to fire even though they live in highly flammable vegetation. Heathlands need fire to maintain their vigour, health and diversity, but the wrong sort of fire can cause local extinction of the parrots.
This project is comparing the survey results against detailed fire history information kept by the New South Wales National Parks & Wildlife Service and information on patch size and isolation is used to determine what fire management is needed where. Without this information it is currently difficult to tell whether a population is in trouble and if the current fire regimes are appropriate and a major outcome of the project will be guidelines for park managers on appropriate burning.
Written by Liz Tasker
Research Scientist, Fire Ecology Unit
Department of Environment, Climate Change & Water, NSW
