Day 24, Bourke to Griffith

Date: Wednesday November 8th 2023

Project: Eastern Australian Waterbird Survey

Observers: Richard Kingsford (UNSW), Jody O'Connor (SA DEW)

Pilot: Thomas Clark

We took off from Bourke and flew over the Darling River on our way to the Macquarie Marshes. 

For the Macquarie Marshes, we use a series of 11 transects which cross from east to west and carve out 200 metre strips over the wetland, 100 metres on either side of the plane for each observer. This gives us an estimate of the number of waterbirds in each of these strips which is then extrapolated to give a total count for this extensive wetland. 

Much of the Macquarie Marshes was dry  

Richard Kingsford counting the transects across the Macquarie Marshes, in the RFO position (right front observer) (Photo G. Borschmann)

It took us about an hour and a half to do this survey. There was a big difference between the Macquarie Marshes in 2023 compared to 2022. The extensive flooded areas with their vibrant green vegetation from last year were replaced, with dry reedbeds, reflected in hues of yellow and brown.

Surveying the Macquarie Marshes, areas which were extensively flooded last year

Some of the wetland areas with water in the Macquarie Marshes

The extensive reed beds in the Macquarie Marshes were much patchier in colour this year, compared to the full vibrant green in 2022

The water had flooded many different areas of the Macquarie Marshes, primarily from the environmental flows held in the dam. It is always great to see the wetland oases. 

Flooded areas in the Macquarie Marshes from environmental flows

There were still quite a few waterbirds in the flooded patches. These included pelicans, egrets, Black Duck, a few Night Herons and all of the ibis species. But nothing like the sort of density that we saw last year, when there was widespread breeding. There were no big concentrations of breeding birds this year. 

We then flew to Dubbo to refuel. After this we headed off for the wetlands of the Lachlan, our last leg this year. First one was Lake Cowal near Forbes.

Lake Cowal was still extensively flooded

This is a very impressive freshwater lake that fills from Bland Creek and the Lachlan River. It certainly didn't have as many waterbirds as we've seen in previous years, particularly when it's drying back. 

Surveying Lake Cowal around the shoreline

But there was a wide diversity, including many different duck species, dominated by Grey Teal, Wood Duck and Black Duck. There were also hundreds of Yellow-billed Spoonbills and cormorants. We also saw the few resident Magpie Geese which have apparently started to nest. There were no colonies of ibis that we've seen in previous years.

Surveying Lake Cowal, with the bug smear

Jody O’Connor after surveying Lake Cowal, in the LBO position (left back observer) (Photo G. Borschmann)