15 May 2010
By Mike Young (retired DEH)
Neophema chrysogaster- Orange bellied parrots are hard to spot.
Orange-Belly parrots have always been an enigma. First of all, they are frequently confused with other neophemas’, particularly elegant parrots.
The four include Elegant, Rocks, Blue-wings and Orange bellies, being individuals that have a tendency to have an orange belly patch.
But again, many don’t while some do have, and hence the confusion.
It’s enough for human nature to come to the fore and help keen bird enthusiasts declare they have seen the “orange belly parrot” more as hope, rather than reality.
Neville W. Cayley is one of the early ones to recognise this confusion.
Then there’s a very close affinity to specific habitats – with coastal salt-marshes used as wintering grounds on the mainland by birds predominantly migrating from Tasmania. This is likely to have evolved (with rising sea levels) from a nomadic “move north after breeding” as a result of the approach of annual snowstorms in the Tasmanian breeding areas.
The “move north” action has extended over time, as the sea encroached over the Bass Strait land bridge while the coastal salt-marsh habitats during winter are still locked in. In the recent past, small groups have turned up at Parnka Point (otherwise known as Hells Gate) in the Coorong and its adjacent Islands. Other examples of the past included the Kingston SE rubbish dump during the 70’s and 80’s and at Werribee on the western shore of Port Phillip Bay in Victoria.
Early records of the orange belly parrot near Adelaide recognise that the first colonisation near the capital resulted in altering the nearby coastal environment very quickly.
The salt-marshes grounds (samphire flats and swales behind the coastal dunes) were levelled and used in early attempts with market gardening. The Outer Harbour area in particular was altered very early.
Orange belly parrots are obviously closely tied to a specific habitat, often leading to higher mortality at the end of the long migration. This is particularly so when an expected food source “is gone.” Orange belly parrots feed on the seeds of various dune grasses, samphire and cape weed. They are also known to eat dandelion seed.
Recruitments from a depleted population would also be reduced so there would be less “starters” at the next onset of winter, with less available habitat at the destination resulting in more losses. And yes, we have been adding to that for a very long time.
This century, we have altered the shorter migration destinations of the Coorong by altering the drainage of fresh water into the Coorong, and destroyed the salt–marsh environments adjacent to the Lower Lakes.
Here, we have barraged the lakes to deny tidal access during times of low river flow, and changed the shoreline to a reed-dominated environment.
Land behind the reeds adjacent to the lakes has been heavily grazed and the salt-marshes salinity is lost because of barrage closures. The key to the loss of orange bellies is more related to the loss of the critical habitat (and changes to that habitat) being more than any other element.
The critical habitat here is in the wintering areas, and not necessarily the breeding areas. The areas they expect as orange bellied parrots to migrate to and not to the breeding areas. However, any habitat loss has to play a part in the success or otherwise of this enigmatic parrot species.
By Mike Young
Edited by K Jury