Migratory shorebirds are a diverse group of species that annually fly large distances from breeding grounds in the northern hemisphere to foraging grounds in the southern hemisphere; and back again. Migratory shorebirds are protected under several international treaties to which Australia is a signatory. As such, they are regarded as Matters of National Significance under the Environment Protection and Biodiversity Conservation Act 1999.
Astron undertook migratory shorebird assessment on offshore islands of the Northwest Shelf to obtain an understanding of the importance of these islands within the East Asian-Australasian Flyway, in particular as staging and roosting points for these species.
Assessments of shorebirds on the islands were conducted in the period from 2013 to 2014. These were part of a much larger migratory shorebird assessment that began in 2003. Typically, assessments are conducted during periods of peak activity for shorebirds; this generally occurs from November to April each calendar year for northern Western Australia. Counts are made within three hours either side of the high tide. Assessments at high tide increase the accuracy of counts because species will congregate in a smaller area of shoreline. A declining trend was seen in some species abundance; however, this is likely to be part of a regional trend of habitat degradation along their flyway rather than changes to feeding or roosting habitat at each individual site.
The zoologists at Astron who undertake migratory shorebird assessments are highly skilled in identifying migratory species and counting their abundance. Assessments of change in species abundance and diversity over time is essential for impacts on shorebirds to be evaluated prior to near shore developments and then managed during construction and operation stages.