The Western Treatment Plant provides a haven for tens of thousands of birds, thanks to a variety of landforms, the permanent water supply and lots of different tree and plant species.
Why a bird haven?
As the efficiency of sewage treatment processes have improved, we no longer use all our lagoons at the Western Treatment Plant. These have become great habitats for birds, as leftover nutrients provide plenty of insects to eat and there’s water all year round.
More than 280 bird species have been recorded at the plant, including migratory shorebirds that travel from Siberia each year.
It is therefore recognised at as a wetland of international importance under the Ramsar Convention, and as one of Australia’s best birdwatching sites.
The Brolga is listed under Victoria’s Flora & Fauna Guarantee Act and is considered vulnerable in Victoria. It is also listed internationally in the International Union for Conservation of Nature (IUCN) ‘Red List’ of threatened bird species.
In recent years a pair of Brolgas have nested successfully in saltmarshes adjacent to the Western Treatment Plant, moving with their chicks onto the Plant’s grasslands to forage. To promote the continued presence of the Brolga and increased numbers, we are undertaking fox control at the plant. Interstingly, two Brolgas were recently sighted at a wetland near the Eastern Treatment Plant, on the other side of Port Phillip Bay, and the furthest east Brolgas have ever been sighted in Victoria. So sewage treatment areas clearly hold attractions for this species.
These beautiful small parrots are ranked, along with the Giant Panda and Siberian Tiger, as an extremely rare and critically endangered species.
Once fairly common in coastal areas, Orange-bellied Parrot numbers have declined dramatically since the 1940s. Drainage, competition for food from introduced and native seed-eating birds, and predators such as foxes and cats are responsible for a population today of only around 50 wild-living birds.
The Orange-bellied Parrot is a migratory bird which breeds in summer in Tasmania and migrates in autumn to the Victorian coast. The parrots spent winter dispersed in areas of coastal saltmarsh from Melbourne to the Coorong in South Australia, in which they forage for the tiny seeds of saltmarsh plants.
The Western Treatment Plant and adjacent areas of coastal saltmarsh are one of the very few places where this species can be seen during winter.
There are many different species of shorebirds at Western Treatment Plant. Of these 75% are migratory, breeding in Siberia and migrating south to avoid the harsh northern winter. The Victorian Wader Study Group tagged some waders and discovered that they have made the round trip of more than 25,000 km up to ten times in their lifetime. Some of Australia’s rarest shorebirds - Asian Dowitcher and Buff-breasted Sandpiper - have been recorded at Western Treatment Plant.
The mudflats along the foreshore feed around 16,000 shorebirds. The discharge of nutrients in the treated effluent enriches the intertidal mudflats and copious amounts of invertebrate food are available when the area is exposed at low tide. At high tide, the shorebirds move inland to secluded sand spits or islets in ponds at the Western Treatment Plant and wait for the tide to fall. The site has the great advantage that, should shorebirds need additional time to feed outside the few hours of low tide, they can move to ponds managed by Melbourne Water to provide alternative high-tide feeding habitat.
Red-kneed Dotterel (Erythrogonys cinctus)
This bird's name is a reference to its long legs that are deep pink to the knee. The dotterel is a small plover and its feeding habits are typical of this family. It will walk or run a few steps along the soft surface of the mudflats, pause upright then tilt forward to jab at food before moving on. Up to 250 Red-kneed Dotterels have been recorded at Western Treatment Plant at one time.
Red-necked Avocet (Recurvirostra novaehollandiae)
The Red-necked Avocet inhabits shallow ponds and flooded inland areas and is one of eight shorebird species that have bred on the Western Treatment Plant. They build nests along the banks of swamps and lagoons, and line them with shellgrit and vegetation. Avocets are easily distinguished from their close relations, the stints, by their beautiful distinctive and slender upturned bill. They feed in shallow water by sweeping the bill from side to side to detect small animal prey.
Red-necked Stint (Calidris ruficollis)
Of all the migratory shorebirds found in Australia, the Red-necked Stint is the smallest and the most abundant. In September, up to 8,000 stints arrive at Western Treatment Plant from their breeding grounds in north-eastern Siberia. They are commonly seen at the Plant, particularly along the mudflats. The Red-necked Stint's name comes from the breeding plumage it displays during its breeding season. While in Australia, the stint is actually grey and white although some individuals begin to exhibit their rufous breeding plumage shortly before departing north on the return leg of their migratory circuit.
The Western Treatment Plant is an important refuge for waterfowl during drought and the duck hunting season. As a permanent wetland, the lagoon system can support up to 120,000 waterfowl, with Lake Borrie alone carrying more than 70,000 in the past.
Chestnut Teal (Anas castanea)
The Western Treatment Plant supports the largest population of Chestnut Teal in south-eastern Australia. Some birds nest in the dense grass surrounding the lagoons and in nesting boxes provided in Lake Borrie.
Freckled Duck (Stictonetta naevosa)
Australia's rarest duck species is the Freckled Duck. The species is fairly regularly seen at Lake Borrie.
Pink-eared Duck (Malacorhynchus membranaceus)
Pink-eared Ducks are found throughout Australia but are not common to coastal areas. They are distinguished by their small size and zebra striped plumage. Although this species of duck does not breed in any great numbers at the Western Treatment Plant, the ponds support up to 40,000 during late summer.
Other birds of interest
Fairy Tern (Sterna nereis)
Fairy Terns hunt in shallow waters by plunge-diving beneath the surface for small fish. They are aggressive and noisy birds that will fly at and defecate on intruders. Terns nest on open sand beaches, free of vegetation and from human disturbance.
Lewin's Rail (Rallus pectoralis)
Lewin's Rail inhabits densely vegetated wetland areas along the coast. One of the most difficult species of bird to find the rail feeds on insects, molluscs and invertebrates, using its long, slender bill to probe in damp mud for food. They are very shy birds and need to have dense vegetation to retreat to, establishing a network of ‘runways’ through which they can move.
Pied Cormorant (Phalacrocorax varius)
The Western Treatment Plant has the largest permanent breeding colony of the Pied Cormorant in Victoria. Between 700 and 1000 pairs of cormorant use inundated trees for nesting and roosting. Initially at Lake Borrie the colony moved to trees in 25W Lagoon where they are more protected from cold sea winds.
Cormorants generally breed in spring or summer yet at Western Treatment Plant they raise their young during winter. The birds feed on fishes in Port Phillip Bay, returning to their nests to feed the young.
Photography by John Barkla, Birdlife Australia.