Date: Wednesday, October 30, 2019
±Ê°ù´ÇÂá±ð³¦³Ù:ÌýEastern Australian Waterbird Survey
Observers: Richard Kingsford & Paul Wainright
Pilot: Tim Dugan
We were out of Mildura early to avoid the heat.
We started our survey at Lock 10 on the River Murray, just downstream of the junction of the Darling and Murray Rivers at Wentworth.
This part of the River Murray is spectacular, particularly in the early morning. There weren’t many waterbirds on the main channel of the river, apart from the odd cormorant, pelican and wood duck, but some of the billabongs beside the river have flocks of shelduck, cormorants, swans and grey teal. The water is much shallower here. Quite a few of these billabongs which held water last year were dry.
As we fly down the main river, we used the locks to define the different parts of the main channel of the river that we survey, starting on Lock 10 and flying all the way down to Lock 2.
We left the main channel of the river to survey Frenchmans Creek which runs from the River Murray to Lake Victoria. This often holds a lot of water because it is used to supply water to users in the Murray. But this year it had dried right back, leaving shallow patches where there was a wide collection of different waterbird species and lots of red kangaroos.
Most of the wetlands close to the river generally had water but those further away were dry; many that were flooded last year didn’t have water. Lake Littra was full on the Chowilla floodplain and with a few hundred teal, hardhead and black duck. Further on, the wetlands to the west were predominantly dry although water was starting to flow into one of the dry lakes, Lake Merreti. Providing habitat for these waterbirds in the middle of the devastating drought is critical as they have nowhere else to go.
One of the more saline wetlands in this part of this riverlands was full of waterbirds. It is every year. This is mainly because a range of crustaceans that can get established in quite high densities, which is great food for avocets, pink-eared ducks and grey teal.
This is quite a contrast to the main channel of the river which continues to have just a few cormorants, pelicans and wood ducks.
There is still enough food presumably for some of the ibis to breed down here where there is a small colony of straw-necked ibis and white ibis on one of the lagoons on the river.
Once we had finished the River Murray, near Lock 2, after flying over a dry Banrock station with no water in its wetlands, we headed for Stockyard Ponds, a salt evaporation basin. These are productive places for some waterbirds which either feed on the aquatic plants (swans) or crustaceans (pink-eared ducks, grey teal).
We reached Lake Alexandrina by mid morning. This is the highlight of the survey for waterbirds. This system is a Murray-Darling Basin and national treasure. It always has thousands of waterbirds - so many more than any other wetland that we had surveyed in the Murray-Darling Basin this year. And even more than some of the big lakes in the Lake Eyre Basin. Despite this, after surveying Lake Alexandrina and Lake Albert today, I was surprised that there weren’t as many waterbirds as we had seen at the height of the Millennium Drought in 2008 when there were hundreds of thousands of waterbirds here. It was still spectacular today with thousands of waterbirds but I would be surprised if we break the 100,000 mark for the two lakes this year (it takes us a while to transcribe our data). I worry that this is just another indication of the long-term decline in waterbird numbers. There were still spectacular flocks of pelicans and cormorants on Lake Alexandrina.
There were also the dependable straw-necked and white ibis colonies on the lakes. Whereas the rest of the Murray-Darling wetlands are languishing in terms of breeding, at least there is some down here. There are also quite a few swans breeding. There is also a large colony of pied cormorants.
Lake Albert is also an important site for waterbirds, and had its usual breeding colony of straw-necked ibis.
Tomorrow, we head down the Coorong and do our second count of the two lakes. It will be interesting to see what we find on the Coorong this year. When we surveyed the southern part of the Coorong last week there were quite a few banded stilts. I am looking forward to seeing them in their spectacular numbers.