Aerial survey of waterbirds in the northern Tanami Desert

A two-day aerial survey was organised by Wetlands International and the Australian National
University (ANU) with funding and/or logistical support from Newmont Mining, the Central
Land Council, other landholders and the NT Government. Wetlands International was
positioned in adjacent rangeland to provide advice to graziers on wetland management –
funded by NHT as part of the Wetland Management Solutions project – and secured top up
funds from NHT to extend its aerial work into the Tanami. At the end of April, Julian Reid of
ANU and Mark Ziembicki of the NT Government undertook the aerial survey. They
collaborated with Roger Potts of Newmont Mining who gathered rare observations on the
immediate response of waterbirds to dramatic local inundation events around the Tanami and
The Granites gold mines.

Flying a zigzag course over multiple sub-catchments in eight hours of flying over two days, the
aerial team observed 19 wetlands comprising coolibah wooded swamps, open lakes, broad
open watercourses and some wetlands with fringing shrubs. From satellite imagery the total
area of water in these surveyed wetlands was calculated to be 17,700 hectares, with another
33,400 hectares not surveyed. Roger Potts’s ground-level observations on waterbird actual
abundance, species composition and breeding at several wetlands allowed a basic calibration
of ground to air counts.

Forty waterbirds were positively identified to species during the aerial survey, while R. Potts
observed a further 16 species from ground level observations between January and May
2006. Although only 15,000 waterbirds were counted from the air, this figure could be scaled
up to almost 70,000 birds when the nature of the habitat of wetlands (an obscuration factor),
partial coverage of certain surveyed wetlands and the usual aerial detection bias were all
taken into account. Given the amount of unsurveyed wetlands in the study region, a
conservative estimate of 200,000 waterbirds resulted.