Environmental Engineering Reference
In-Depth Information
The Use of Aerial Surveys for the Detection
of the Brolga
Grus rubicunda
Through
South-West Victoria: Key Considerations
for the Wind Industry
David Wilson and Aaron Organ
Abstract
The brolga
Grus rubicunda
breeds primarily in shallow freshwater
wetlands and is classified as Vulnerable in Victoria. Specific guidelines have been
developed to mitigate potential impacts of the wind industry on brolga populations.
Identifying brolga nest sites is a key aspect of these guidelines and aerial surveys are
suggested as one method. We used aerial surveys to identify brolga nesting sites
over a large area of south-western Victoria during the 2009 and 2010 breeding sea-
sons. We surveyed approximately 800 km
2
over the two seasons, and detected 44
nests which were subsequently ground-truthed. Of these nests, nine were confirmed
as belonging to brolgas, 14 as belonging to black swan
Cygnus atratus
and 21 were
either abandoned or not accessible. Aerial surveys covered a much larger survey
area over a shorter time period compared with ground surveys (approximately half
the time), and covered wetlands not otherwise easily accessible (e.g. sites located
away from roads and/or on private property). Given the difficulties in distinguishing
between brolga and black swan nests, it is imperative that wetlands are ground
truthed to accurately identify nests. Given that not all nests are active concurrently
in a given season, our results reveal that at least two aerial surveys are required
across a study area to detect 75 % of the brolga nests in a season.
Keywords
Brolga•Crane•
Gruidae
•Detection•Nestsurveys•Windfarms
Introduction
Cranes,Family
Gruidae,
are an iconic group of 15 bird species spread across much
of the world, with 10 of these species listed as threatened (del Hoyo et al.
1996
). The
brolga
Grus rubicunda
is widespread and relatively common in northern and east-
ernAustralia,withanisolatedpopulationoccurringintheFlydeltaregionofPapua
