WILDLIFE SCIENCE Bird call technology takes flight
Advanced acoustic devices are helping ornithologists unobtrusively identify and study secretive, rare species
THE UNKNOWN call – a soft staccato clicking sequence – that Robin Colyn detected in his novel collection of audio recordings had never been heard before. It didn’t match previous records for any species, bird, mammal or amphibian, found in South Africa’s wetlands.
“The call was unique in that it differed significantly from most other flufftail species and occurred within an extremely low frequency range, making it difficult to distinguish among the wetland soundscape of other birds and frogs,” says Colyn, an ornithologist at Birdlife South Africa (BLSA).
As he worked through the recordings, from the Muddelpunt wetland near Dullstroom, Colyn found more evidence of this clicking sequence.
It would turn out that the call, which corresponded with camera trap photographs of a territorial male white-winged flufftail, would solve one of South Africa’s greatest ornithological mysteries: the call of the enigmatic, critically endangered white-winged flufftail.
“This discovery is another first for science and a major development in our journey to conserving these birds,” enthuses Dr Melissa Whitecross, threatened species project manager: raptors and large terrestrial birds, BLSA.
Bird calls are used worldwide to record the presence of various species and to help determine population sizes, but the white-winged flufftail, which is on the brink of extinction, is one of the only bird species in the country for which no known call has been officially described since its discovery in 1877.
In July, a BLSA team, including Whitecross and Colyn, travelled to Ethiopia to do habitat surveys in the known breeding sites for the whitewinged flufftail. “Our mission was two-fold, as we installed the same audio devices into the Ethiopian wetlands and in the first day of recording at a key white-winged flufftail site, we detected the same clicking sequence that had been recorded at Middelpunt,” says Whitecross.
“The call has not remained undiscovered because of lack of effort, as numerous expeditions have been made over the past 20 years to record and/or identify the call,” says Colyn.
“This species, largely due to its very secretive behaviour, low density, preference for dense wetland vegetation and cryptic colouration has resulted in it being one of the most difficult wetland species to study in Africa.”
The identification and recording of the species’ call for the first time, together with the discovery of it breeding in South Africa earlier this year, has “reshaped our understanding of, and ability to, conserve the white-winged flufftail”, says BLSA.
“Knowing the call will enable us
A BIRD in the hand: an elusive white-winged flufftail.
THE acoustic device used to record the call.