Birds of a feather

Pelicans in the driveway, thousands of kilometres from the sea…what exactly does Naree Station Reserve look like when birds come to breed?

A cacophony of sound with chicks of different sizes everywhere, adult birds going up and down like a highway to the swamp to get food… Nests on all different levels making the trees look like they are laden with exotic fruits...”

This is how one of Australia’s foremost waterbird experts Dr Richard Kingsford, Director of the Centre for Ecosystem Science at UNSW, remembers some of the previous bird breeding events at Bush Heritage’s Naree Station Reserve in north-western New South Wales.

The renowned river ecologist has been visiting Naree, Budjiti country, since 1986 as part of a long-term study tracking waterbird populations in the Murray-Darling Basin, which contains nearly half of all Australia’s colonial waterbird breeding habitat (‘colonial’ meaning birds that breed and nest in colonies).

A couple of years ago, his team published a paper that found waterbird numbers in the Murray-Darling Basin have dropped by about 70% over the last three decades, due mainly to increasing water extraction and reduced flooding, as well as drought.

Colonial waterbirds breed opportunistically in response to floods and flows that fill up the wetlands and swamps in which they build their nests.

Such events are rare, but this year, Naree and surrounds were in luck. At the time of writing, the reserve’s swamps are full, a rare sight since Bush Heritage purchased the ex-sheep and cattle station eight years ago.

Big rains at the start of Autumn, including 116mm in one day, one of the single biggest falls in the area for a generation, filled the reserve’s ephemeral swamps, while good flows down the Warrego River flushed fresh water into the Cuttaburra Creek system, filling Naree’s alluvial floodplains.

For Reserve Manager Greg Carroll, who lives and works on Naree full-time, the transformation was immediate and like nothing he’d seen there before.

“I started noticing all these different waterbirds, birds that I don’t normally see here,” says Greg. “They were turning up because there was water but they were also turning up because there was lots of food.”

The Pelicans were first to arrive, taking to the water in their hundreds. Then came all the ducks, Yellow-billed and Royal Spoonbills, Great Cormorants, Terns and Black Swans.

“I hadn’t seen Black Swans here before but near the homestead there was a swamp that’s never usually full and there were Black Swans paddling around it with their cygnets following behind them.”

University of New South Wales PhD student Roxane Francis, who is supervised by Dr Kingsford, headed out to Naree a few weeks after this initial influx to check up on the breeding activity.

“Some of the wetlands on Naree are enormous,” says Roxane. “Even if you stood on the edge and walked around the whole thing you still wouldn’t have a vantage point of the centre.”

In the past, scientists would have conducted surveys manually from a light aircraft or a kayak, but today Roxane does her surveys by drone, allowing her to gather high resolution images of nesting areas with minimal disturbance to wildlife.

From about 70 metres up, her drone takes photos every couple of seconds. A live view on her mobile device allows her to send the drone lower – to around 30 metres off the ground – when nests are spotted to get a better look.

From above, Roxane says Great Cormorant nests look like bullseyes – stacks of dark sticks ringed by white bird scat. Easy to spot.

“In your head it’s like ‘Oh, nests, they must be really hard to see from 70 metres in the air’, but Great Cormorants are quite a big bird so they make quite a big nest,” explains Roxane.

Later, the drone images are digitally stitched together and voila, a picture is born – what’s known in the field as an orthomosaic.

As well as determining breeding activity, these detailed grids will allow Bush Heritage to compare flood extent at Naree in the future.

This year, the reserve has claimed the title of outback bird nursery. Colonies of inky black Great Cormorants were recorded breeding on two of the seven wetlands surveyed, with 80 and 26 nests found in each.

Singular Black Swan and Black-winged Stilt nests were also recorded, as well as some juvenile Australian Darters which could have fledged on Naree or elsewhere.

“It’s not a massive breeding event but it’s a fair size,” says Roxane. “Considering that the area is semi-arid, it’s pretty special to get enough water in the region to have birds breeding.”