GERMANY:Bird species are disappearing from Europe's forests, but a new approach may help at last to assess the situation. Researchers at the University of Bonn in Germany have developed a voice detector for birds that can recognise the characteristic songs of different species.

By deploying the microphones in the wild, the scientists can record the signature tunes of various species over months and provide the kind of continuous monitoring that would otherwise require flocks of ornithologists.

The bio-acoustic computer software can then sift through the recordings and give a read-out overnight of how many species of birds were singing and for how long.

Researcher Daniel Wolff analysed the birdsongs of Savi's warbler and the chaffinch and transferred the characteristics of their tunes to computer algorithms, which the detector could then recognise. Trials showed that despite interference from rain, wind and even amphibians, the gadget reliably picked up the correct birdsongs.

The system can help speed up and improve monitoring, Wolff told Innovation.

"Bio-acoustic systems provide an essential tool for the biologist," he said.

"A major goal for future work is to broaden the set of species which can be simultaneously detected with such detectors.

"The precise localisation of individuals is also a major issue. The more sophisticated these systems get, the bigger the areas and time spans which can be observed," he says.