Waterbirds and their habitat requirements

3 species.  Musk Ducks, Blue-billed Ducks and the Little Black Cormorant have all been recorded in 6-8 months of the year. The Australasian Darter has been recorded in only 3 months. All require relatively deep water (1-2 meters) to feed. The reason these birds are not recorded throughout the year is their requirement for a sustained deep wetland.

There are no records of any of these water birds nesting at Perry Lakes although it is likely that Musk Ducks have bred there.

Image of Little Black Cormorant by Ian Stewart.

4 species.   Eurasian Coot and Australasian Grebes have been recorded in most months of the year indicating that the lower water levels at Perry Lakes (i.e. prior to pumped inflow) was suitable. Both species have bred successfully at Perry Lakes. Both species occur commonly in a range of other urban wetlands.

Little Pied Cormorant and Hardheads have been recorded in 6 months of the year. They are not known to have bred at Perry Lakes.

Image of Grebe with chick by Ian Stewart.

4 species   

Pacific Black Ducks are very common in urban wetlands and occur in all months of the year at Perry Lakes, where they have bred successfully. Their habitat versatility enables them to survive and thrive in sometimes limiting conditions.

Grey Teal are also versatile in habitat use and commonly occur in a range of wetlands. They have been recorded at Perry Lakes for only 10 months of the year and have not bred there so there are limiting habitat factors. Similarly, the Australasian Shoveller has not been recorded for all months of the year and is not known to have bred at the lakes. 

Pink-eared Ducks are specialised filter feeders so are more specific in food resource requirements. They breed readily in urban wetlands and have bred at Perry Lakes, most likely on the East Lake island.

Image of Pacific Black Duck by Joseph C Boone, CC BY-SA 4.0 via Wikimedia Commons.

2 species.  Benthic browsing waterbirds feed predominately at the bottom of the water body. Black swans have been recorded in all months and have bred at Perry Lakes. Their long necks enable them to forage on benthic (bottom) algae and aquatic plants.

Australian Shelduck have also been recorded in all months although have probably not bred at Perry Lakes. They are usually observed in pairs or small groups, not in the large moulting groups as occurs at Galup (Lake Monger) and at many non-urban wetlands..

Image of Black Swan by EllieRH, CC BY-SA 4.0 via Wikimedia Commons.

6 species. White-faced Heron have been recorded in all months, usually as a solitary record and have not been known to breed at the lakes. Similarly, Black-winged Stilts are often recorded but do not consistently occur or breed at Perry Lakes.

Both Great Egrets and Yellow-billed Spoonbills have been recently recorded in relatively high numbers (~35 individuals for both species) in East Lake (March, 2024). This is unusual for Perry Lakes and is probably due to food abundance compared with other urban wetlands for this time of year. It is speculated that Gambusia fish were the cause of frenzied feeding for these two species although the abundance of fish or other food resources is not known. Neither of these species, nor the White-necked Heron have bred at Perry Lakes.

The Nankeen Night Heron has been recorded for only 8 months, although it is possible that being nocturnally active, it occurs at Perry Lakes throughout the year undetected. It is not known if this species has bred at Perry Lakes, although juveniles have been observed there. 

Image of Nankeen Night Heron by Ian Stewart.

9 species.  This is the largest and possibly most significant feeding group at Perry Lakes when considering water level management, especially in relation to mudflat exposure.

Purple Swamphen and Dusky Moorhen are consistently recorded at the lakes and are known to have bred there. Australian White Ibis and Straw-necked Ibis are regular, though not consistent, visitors which have not been recorded to have bred at the lakes.

Buff-banded Rail are now commonly seen at the lakes and have bred there recently. The three species of crake are being recorded more frequently in recent seasons, probably due to pumped water inflows and possibly due to heightened observer interest. It is not known if the crakes have bred at the lakes.

There is just one recording of a Black-fronted Dotterel at Perry lakes; however this species, as well as other waders could be more commonly recorded if water levels were managed to expose moist mudflats.

Image of Purple Swamphen by Toby Hudson, CC BY-SA 3.0 via Wikimedia Commons.

6 species.  While many birds use wetland fringing vegetation for refuge, there are 5 species of waterbirds that dwell in this habitat.

Australian Reed Warblers and Little Grassbirds have been recorded for 11 months of the year and are very likely to be there all year but difficult to detect when non-vocal. There are no records of these species breeding at Perry Lakes, although it is highly likely that they do.

Australian Wood Duck are commonly observed and often with chicks or juveniles suggesting they have bred at the lakes or in woodland nearby. They graze on land adjacent to the wetlands and will move into the waterbody for refuge when disturbed.

The Glossy Ibis is an opportunist species that is occasionally recorded when suitable food is available.

The Sacred Kingfisher is a winter migrant. It is probably under-represented in the records and it is expected that it will have bred using tree hollows in or near the lakes.

Image of Sacred Kingfisher by Harrison Osgarby

Almost half of the identified water bird species (16) are in the Shallow Water Forager and Wetland Margin Forager groups. It is these two groups for which lake level management is critical to ensure they stay and breed successfully at these wetlands.

There is a need for seasonal measures of food resource availability, including fish, aquatic invertebrates and other identified food options.

While it is known that some waterbirds are breeding successfully at the Perry Lakes wetlands, there are no consistent written records of them doing so. Casual observations are made of common waterbirds that breed there but not for most other species.

Systematic monthly bird surveys of the lakes would provide a more robust record of waterbird occurrence throughout the year. Surveys should record a measure of abundance as well as occurrence (most previous bird survey information does not include the number of each species recorded).

The pumped inflow to Perry Lakes provides many opportunities to provide baseline information and on-going monitoring of water bird habitat restoration. In addition to quantified bird surveys, there should be measures of seasonal food abundance, habitat structure and function as well as routine measures of water levels and water quality. The prime opportunity is to measure changes over time with controlled water inflow, and for comparison of water bird use between east and west lakes.