Ibis breeding event at Booligal Blockbank – 2012

Ibis breeding event at Booligal Blockbank – 2012

Booligal Ibis breeding Sept 12

Continuous flows to Merrimajeel and Muggabah creeks and extensive inundation of the Booligal wetlands occured as a result of storm and flood events of March 2012. From late june flows have benn maintained by a series of translucent environmental flows  released in the Lachlan under WSP rules.

On 29/9/12 aerial inspection of Merrimajeel Ck confirmed the presnce of straw necked ibis and white ibis in the early stages of trampling lignum and nesting on Booligal State Conservation Area (SCA) upstream of the Booligal block bank site. At that stage the breeding event consisted of >400 straw necked ibis and >100 white ibis as well as scattered spoonbills. Subsequent aerial inspections and onground observations indicated the breeding event was expanding slowly and doubled in size, although restraicted to Booligal SCA. Observations showed an additional 200 (approx.) glossy ibis nesting.

On 11/10/13 to prevent water levels at the breeding site declining in the absence of active flows in the Merrimajeel creek, boards were installed in the downstream Blockbank regulator.

To avoid receding water levels at the breeding site that would lead to abandonment of nests and failure of the breeding event, a delivery event with adaptive e-water for a further 90 days was proposed. It was thought that the 90 day flow would enable the birds which recently arrived be supported until their young are able to fly and forage. A proposed 4,500ML at an average flow of 50ML/day water order was placed on 25/10/12.

On 29/10/12 reports were received that birds appeared to be abandoning nests. Investigation on 1/11/12 confirmed that over 1000 newly constructed nests were abandoned so the water order was cancelled. 446ML were delivered with the boards at the Booligal Blockbank retained to slow water level decline so as to enable the small number of young birds at the site achieving independence.


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Written by Joanne Lenehan