91³ÉÈ˰涶Òô

Date: Wednesday, November 16, 2016

±Ê°ù´ÇÂá±ð³¦³Ù:Ìý

Observer: Richard Kingsford

An early start again on our last day of surveying. Today it was all focused on the Macquarie Marshes, about forty minutes southwest of the Darling River at Bourke.

A billabong north of Bourke on the Darling River

We started on the most northern part of the Macquarie Marshes. This is one of the most magnificent wetlands of not only the Murray-Darling Basin but in Australia. It certainly has the largest number of breeding colonial waterbirds, the ibis (three species), egrets, night herons, egrets and spoonbills. It is an absolutely wonderful part of the world and the opportunity to fly over its full magnificence was very special. It has so many different habitats. This undoubtedly contributes to the incredible diversity of waterbirds.

Agriculturally developed land juxtaposed with natural wetland

Flying over the extensive river red gum forests

The marshlands in their full glory

The extensive reedbeds and lagoons of the Macquarie Marshes.

Open waters across the Macquarie Marshes

Lagoons across the Macquarie Marshes

The flight was exhilarating. There are few better places in Australia to get a bird’s eye view of the biodiversity of a river. The variety of different vegetation types transition quickly as you fly over. I was pleasantly surprised by the number and diversity of waterbirds in the wetland. We have tape on the struts of the wings that ‘cut’ a 200m imaginary swathe on either side of the plane, as we fly east west along transects. There were lots of straw-necked ibis. It was great to see.

Surveying the variety of habitats across this amazing wetland

Surveying the reedbeds of the Macquarie Marshes

The Marshes are well known for the breeding of colonial waterbirds (the herons, egrets, ibis and spoonbills). It is always great to see them here. We diverted from some of the transects to see if there were colonial waterbirds breeding in their traditional sites. When there is a maximum breeding event underway, there can be up to 80,000 pairs of waterbirds in the Marshes, including night herons, intermediate egrets, cattle egrets, little egrets, large egrets, royal and yellow-billed spoonbills and the three ibis species, straw-necked ibis, white ibis and glossy ibis. This year is a very impressive breeding event but probably only about 30,000 pairs with only six of the 20 traditional breeding sites in action.

One of the large ibis and royal spoonbill colonies

Another of the large colonies of straw-necked ibis with a few white and glossy ibis

One of the really interesting things that has happened in recent years is that the magpie geese are moving back to their old territory of the Murray-Darling Basin. So a big surprise to me was the number of magpie gees in the Marshes and not only that – nesting birds in clumps.

Magpie geese nesting in the Macquarie Marshes.

It is not only the invertebrate and plant eating waterbirds that capitalise on the floods but even the fish eating birds are here in big flocks.

A large pelican flock on one of the lagoons

The Macquarie Marshes is compromised by the development upstream with river regulation, the building of dams allowing the diversion of its life blood – water. But there is also development within the Macquarie Marshes. As places dry out and don’t get flooded as regularly, there is temptation to start cropping the wetland areas which then get destroyed during a flood. This makes it very difficult to use environmental flows to increase the flood because this can cause further damage but it is critical to increase the size of the breeding events. 

Cropping within the Macquarie Marshes, showing the natural flow patterns.

Surveying the Macquarie Marshes

There is always something new to see, not just in the waterbird world but also the water landscape. The patterns, the colours and the systems are incredible.

Colours and patterns

It’s a great flood but it isn’t everywhere. We flew over large areas of dryland wetland which hadn’t been flooded. You could see that this wasn’t a ‘super-flood’ with many obvious wetland areas not receiving water.

Even as I write this, the Murray-Darling Basin Authority will next week decide on the amount of environmental water to be provided to the rivers of the Darling, including the Macquarie River which supplies the Macquarie Marshes. There is talk that the Government will recommend reducing environmental flows to the Macquarie Marshes which flies in the face of the scientific evidence which categorically shows that the Marshes are in trouble and they need all the water they can get. This will also make it difficult for Australia to argue to other nations of the world that we are properly looking after one of our more important wetlands, an internationally listed site under the Ramsar convention.

We got a chance to go into the wetlands on the water which was fabulous. As much as I like surveying these wonderful areas from the air, there is nothing that beats getting the ‘mud between your toes’ and being in amongst it. The young straw-necked ibis are now almost fully fledged, flapping and exercising their wings regularly.

Young straw-necked ibis

Hundreds of young straw-necked ibis about ready to fly

The parents are still shuttling back and forth to feed them from even dryland areas where they pick up grasshoppers or wetland areas with frogs and other aquatic invertebrates.

Parent straw-necked ibis, showing its lovely neck plumes from which it gets its name

It is not just the colonial waterbirds that are breeding but many other waterbirds are also breeding in large numbers including many duck species.

A family of pink-eared ducks

Tomorrow we return to Sydney after finishing the 2016 aerial survey of waterbirds, 27 survey days later.