|Most recent IBA monitoring assessment|
|Year of assessment||Threat score (pressure)||Condition score (state)||Action score (response)|
|2008||medium||not assessed||not assessed|
|For more information about IBA monitoring please click here|
The Werribee & Avalon IBA consists of wetlands from the mouth of the Werribee River to Avalon saltfields, on the shores of Port Philip Bay, south-west of Melbourne. Much of the area consists of the sewage treatment ponds of the Western Treatment Works, combined with coastal mudflats past the Point Wilson Explosives Area, to include all of the Avalon saltworks and Limeburners Bay. The sewage treatment works treats 60% of Melbourne's wastes in a series of aerobic and anaerobic lagoons and Lake Borrie, with patches of reeds and other wetland vegetation, and irrigates treated effluent onto adjacent pastures. The coast includes saltmarshes, intertidal mudflats and a small area of mangroves. The site is flat, has an annual rainfall of about 750 mm and mean maximum temperatures of 24°C in January and February to a mean minimum of 7°C in July. All of this area except for the Avalon saltworks is included within the Port Phillip Bay & Bellarine Peninsula Ramsar Site which also includes extensive areas of pastoral grasslands of little ornithological value within the Western Treatment Plant.
Significant populations of Banded Stilt (max 1846 in 2004), Curlew Sandpiper (declining, max 5074 in 2004 but previously 13,323), Red-capped Plover (max 202 in 1996), Double-banded Plover (max 519 in 1996 but subsequent counts below 310; previous max 955 and long-term mean 508), Black-fronted Dotterel (max 303 in 1983), Pied Oystercatcher (max 159 in 1985) and Red-necked Avocet (max 1166 in 2003), Black Swan (max 6879 in 2006), Hardhead (max 9784 in 2004), Pacific Black Duck (max 2231 in 2001), Great Crested Grebe (max 633 in 2005), wetland passerines, raptors, foraging site for Fairy Tern, breeding site for Pied (700 pairs; Environment Australia 2001) and Little Pied Cormorants and regular records of Australasian Bitterns, but probably not breeding (ARI database on behalf of Melbourne Water Corporation and Australian Wader Studies Group Database). Vunerable Fairy Tern recorded in 31 of 196 (16%) and near threatened Flame Robin recorded in eight of 196 (4%) Atlas of Australian Birds surveys from 1998 to 2008 (Atlas of Australian Birds database). Striated Fieldwrens are common in suitable habitat (G. Dutson pers. obs 2007); recorded in 67 of 196 (34%) Atlas of Australian Birds surveys from 1998 to 2008 (Atlas of Australian Birds database).
Non-bird biodiversity: Contains numbers of the Striped Legless Lizard and Growling Grass Frog (threatened in Australia) and Fat-tailed Dunnart (threatened in Victoria).
BirdLife International (2020) Important Bird Areas factsheet: Werribee and Avalon. Downloaded from http://www.birdlife.org on 28/02/2020.