WILDLIFE SCI­ENCE Bird call tech­nol­ogy takes flight

Ad­vanced acous­tic de­vices are help­ing or­nithol­o­gists un­ob­tru­sively iden­tify and study se­cre­tive, rare species

Saturday Star - - METRO - SHEREE BEGA [email protected]

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.

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