Birds provide important ecosystem functions and provide pleasure to the community through their colour, calls, flight and behaviour.
The strategy will consider opportunities to enhance bird values through on-ground works and other initiatives e.g.
- Planting native vegetation along streams to provide habitat
- Altering flow regimes and water levels in wetlands
- Providing access and viewing points for bird watchers
Birds are one of the most visible, studied and monitored classes of animals to underpin the development of this draft Healthy Waterways Strategy.
Bird presence has a positive influence on how people feel about the health of waterways as they bring pleasure through their colour, calls, flight and other behaviours. They also provide important ecosystem functions such as pollination, seed dispersal and regulation of insect populations.
Many birds have become specialised to certain wetland habitats or depend on regular access to water for many life processes such as feeding or breeding.
Crakes, Rails and Bitterns (marsh birds) generally rely on dense vegetation found around wetlands and waterways for cover and protection during breeding, moulting and daily foraging. Some birds, such as the Black-winged Stilt, rely on variations in natural water depths and flows to trigger breeding.
Many rivers, wetlands and estuaries are popular spots for birds and birdwatchers. Data has been collected from 20,370 bird surveys at wetlands or along waterways in the Port Phillip and Westernport Region. Most of these come from voluntary bird surveys compiled by BirdLife Australia.
Native water-dependent bird species are considered in two subsets: streamside (riparian) and wetland birds.
The current status of birds in each catchment is determined through survey data from Birdlife Australia’s Bird Atlas. Only data from selected, standardised surveys within 250 metres of a waterway or wetland were included. The status score is determined by summing the reporting rate of expected riparian species between 2012 and 2017. This gives us a measure of how many expected species were observed and their relative abundance.
We are still developing an appropriate measure of wetland bird condition which is difficult because wetlands vary so much both individually and over time. So it is difficult to derive a useful measure of wetland bird condition over an entire catchment.
There are 295 bird species recorded, of which 126 species are riparian specialists. Overall, the Dandenong catchment received a high score for birds.
Parts of the catchment are of international significance for migratory shorebirds. This includes the sharp-tailed sandpiper found in the Ramsar listed Edithvale-Seaford wetlands. The extensive network of wetlands along Dandenong Creek also provide important drought refuge for waterfowl (e.g. Chestnut teal, grebes and coots). Threatened species including the Australasian bittern and blue-billed duck can also be found at wetlands within the catchment.
There have been over 350 species of bird recorded, of which 95 species are considered riparian specialists.
Overall, the Maribyrnong catchment received a moderate score for riparian birds.
There are 134 expected riparian species. Overall, the Werribee catchment received a moderate score for riparian birds. Of the 12 sub-catchments, 1 had a high condition score, 6 had a moderate score, and 5 had insufficient data to generate a condition score. There are also 57 species considered wetland-specific across the region. But wetland bird condition could not be assessed at the catchment scale because of the limited number of surveys – other than intense monitoring at the uniquely different Western Treatment Plant.
There have been 249 species of bird recorded, of which 131 species are expected in riparian habitats. Much of the catchment is in good to moderate condition for riparian bird values. The Mornington Peninsula South-Eastern Creeks sub-catchment has been assessed as very high and Dalmore Outfalls as low. However, sub-catchments in the east of the catchment have insufficient observations to support an assessment.
The Westernport catchment has important bird habitats. This includes:
- Ramsar-listed Western Port with its extensive network of mangroves, saltmarshes and mudflats
- Riparian areas in forested headwaters
- Tootgarook Swamp on the Mornington Peninsula
- Bird colonies on Phillip Island
These areas include threatened species such as Australasian Bittern, Hooded Plover, Eastern Great Egret and White-bellied Sea-Eagle, and important migratory species such as Eastern Curlew, Red-necked Stint and Curlew Sandpiper.
The score for streamside birds across the catchment ranges from very high to low. However, half of the 24 sub-catchments did not have enough bird survey information over the past five years to generate a robust condition score. This riparian bird score is calculated from an ‘expected’ list of 153 native species of bird for the Yarra catchment and considers both species richness and abundance.
Species listed as nationally-threatened in the catchment include: the Swift Parrot, Australasian Bittern and Helmeted Honeyeater.
- Lack of native streamside and landscape vegetation
Vegetation provides the essential habitat framework for streamside and wetland birds; for their feeding, roosting, moulting and breeding. Vegetation clearing reduces habitat extent and tends to degrade remaining habitat quality, limiting the variety of bird species found.
- Introduced pests
Species such as foxes, dogs and cats prey directly on eggs, chicks and adult birds. The presence of introduced predators can deter birds from frequenting an area, and may prevent breeding attempts.
- Flow conditions
Some birds require ecological triggers (such as changes in water flow) and seasonal changes for natural processes such as breeding.
Potential management actions
- Implement environmental flow regimes
Provide and protect appropriate flows to ensure that birds are protected from loss of habitat and food sources such as fish and macroinvertebrates.
- Reduce populations of introduced pests
Protect birds from disturbance and predation by foxes, dogs and cats.
- Protect, improve and maintain habitat quality
Protect habitat by controlling, weeds, undertake works in and beside waterways, and establish new vegetation zones.