Date: Wednesday, October 14, 2020
Project: Eastern Australian Waterbird Survey
Observers: Richard Kingsford UNSW, Paul Wainwright DEWHA
Pilot: James Barkell NSW National Parks & Wildlife Service DPIE
We headed to the Lachlan this morning after leaving Hay. Today was a Lachlan River day, as we surveyed all the major wetlands on this river, from the bottom to the middle of the river, apart from Lake Cowal. This is where all the major wetlands can be found. Unfortunately, the sustainability of these magnificent wetlands and their waterbirds, not to mention the native fish and plants, are threatened by the proposed doubling of the capacity of Wyangala Dam. This major proposed project, funded by the NSW and Australian Governments, will have significant negative impacts on environmental and cultural values and affect the grazing production on the floodplains and wetlands of the Lachlan River. You can find out more about the potential impacts here.
First up for today’s survey was the Cumbung Swamp. This extensive reed bed swamp and its river red gum forests are now a major focus for conservation, headed up by The Nature Conservancy and the Nari Nari Tribal Council in partnership with Tiverton agricultural company. The environmental flows were working their way down through the swamp, trickling out across the floodplain, making intricate patterns of vegetation and water.
There weren’t that many waterbirds on the Cumbung Swamp, except where the flood front was working its way across the floodplain. It must be here where the floods are drowning small terrestrial invertebrates and there are easy pickings. Some of the water was also starting to make its way through the red gum forest. I would expect the numbers of waterbirds to keep increasing here over the coming months. There were a couple of white ibis nesting; they are always the first of the ibis species to get going.
There were a couple of freshwater lakes just to the west of the Cumbung which would have flooded naturally in the past, with overflow from the Cumbung but now receive water via a channel, making one permanent. The other one was dry but it was great flying down the middle of the wetland. The permanent lake was starting to dry back but not good habitat for waterbirds because it is permanently full. Still – it was spectacular flying down the middle of the lake.
We started to work our way north up the Lachlan, meandering like the river, except in the opposite direction to river flows. A small lake on the side of the floodplain of the Lachlan was a revelation. This was our first full on experience of the Lachlan in all its glory, with lots of waterbirds, a taste of what was to come during the Lachlan surveys. Flocks of whiskered terns, grey teal, pied stilts and pink-eared ducks swarmed from the edges as the plane came along. And there were coot all across the surface of the lake.
Further to the north, the Muggabah, Merrimajeel, and Merrowie Creeks were winding their way across the floodplain, their water making amazing intricate patterns and bringing this amazing floodplain to life. We worked our way across these little channels. Everywhere there were small flocks of grey teal, wood ducks, hardhead, the odd freckled duck and Pacific herons.
Lake Waljeers was our next major wetland to survey. It often holds water for longer than other places in the Lachlan and from a waterbird point of view can be disappointing. The almost permanent water in these systems is the antithesis of productivity. They need the gentle flooding and drying to produce their magic. And the lake was another revelation. Like race callers, we had to call the hundreds of grey teal, whiskered terns, coot, hardhead and pied stilts that took off from the edge of the wetland as we flew around the margin of the lake. There were so many coot and hardhead in the middle of the lake that we even had to do a run down the middle, which isn’t usually necessary because the waterbirds tend to hug the edge of the lake, where the shallow water has the most accessible food.
There were also a few small lakes with water on the floodplain. Most weren’t full but already creating great waterbird habitat.
The most extensive wetland areas out here were the myriad of small creeks and channels that spread like fingers across this floodplain. And this is really only a small flood, nothing like the size of the 2016 flood which really made things hum with a colony of more than a hundred thousand breeding straw-necked ibis and other spoonbills and ibis. Today was a bit of a taste of what the Lachlan floodplain could do. The long duration of the flood spread widely across the floodplain. And it’s not just the waterbirds that benefit. The waterbirds reflect the ecosystem. Where we see lots of pelicans, migratory wading birds, herons and ducks, there is lots of their food. That means there are fish, frogs, invertebrates and vegetation flourishing. Not only is the environment benefiting but so are the many graziers as the floods rejuvenate the country. It is some of this environment water which would go with the doubling of Wyangala Dam.
Flying low over these wonderful wetlands is an experience I can never tire of, even though I have been doing this for more than three decades. Waterbirds were everywhere along the tiny creeks and channels. And a great diversity. That’s the other thing that makes the Lachlan such a wonderful floodplain river system – the incredible diversity of life, including waterbirds. These floods were the result of water passing through Wyangala Dam as part of what is called a ‘translucent’ environmental flow; some of the water flowing into the Wyangala Dam with the recent rains was allowed to go naturally down the river.
We eventually finished the Lachlan River wetlands, after about another couple of hours of back and forth and headed off for Lake Brewster. This was once a natural wetland on the Lachlan which was made into a dam to store water. But today it was operating like a natural wetland, as the water had only just arrived a few months earlier. There were thousands of waterbirds, ibis, herons, egrets, black duck, grey teal, spoonbills and pelicans. Sometimes the pelicans are in such large numbers, nesting on the islands, but not today. Instead, the swans were at it, with their platform nests on the islands. It was great to see but hard work counting, given there were probably well over twenty thousand birds on the lake.
Obviously with so many waterbirds, there had to be a lot of food. The place was thick with invertebrates which the plane picks up all the time. Our windscreens need a thorough clean when we have been over a really productive wetland, such as those on the Lachlan. As a result the gopro can get a little splodgy and not so clear.
So we had to stop in what looked like a wheat field to change over the cameras and have a stretch. Actually it was an airstrip near Lake Cowal. Afterwards we headed to Parkes to refuel and the night.
Blog by Richard Kingsford