Why straw-necked ibis?

Why track the movements of straw-necked ibis?

Straw-necked ibis (Threskiornis spinicollis) were chosen for satellite tracking for a range of reasons:

  • Straw-necked ibis are known to nest in large numbers in nearly all Murray-Darling Basin wetlands with environmental flows
  • They are thought to use a range of habitats dispersed across the Basin, from wetlands to dry pastureland, meaning their habitat requirements must be managed from a local to a Basin scale, and possibly at an even wider spatial-scale
  • The locations of their major nesting colonies are known, as are some of the breeding thresholds related to flows and inundation
  • These nesting colonies are in locations accessible to researchers
  • They are a waterbird species who are highly mobile and nomadic and whose movements are closely tied to water availability within inland floodplains and wetlands
  • They are a species of particular interest to water managers
  • Little is known about their movements post-breeding
  • They are of a large enough size to carry a satellite tracker

What about tracking other species?

We are also interested in tracking a species representative of a dominantly water-foraging colonial-nesting waterbird, such as a royal spoonbill (Platalea regia). Royal spoonbills depend on surface water for feeding, meaning their foraging habitat requirements are even more closely tied to water than straw-necked ibis. Royal spoonbills breed in colonies of reasonable numbers at most major Murray-Darling Basin wetland breeding sites in most years. They also nest next to ibis colonies, making them relatively easy to find and access.

The spatulate-shaped bill of the royal spoonbill is designed for surface water feeding on fish, crustaceans and aquatic invertebrates. Image credit: CSIRO

The brolga (Grus rubicunda) is another species we are interested in, however unlike the royal spoonbill, brolgas forage in both terrestrial and aquatic habitats. Brolgas are currently listed as ‘vulnerable’ in NSW, Victoria and South Australia, so understanding their habitat requirements within the Murray-Darling Basin over the coming years is crucial.

Other species of interest for satellite tracking because of insufficient knowledge of their movements include the yellow-billed spoonbill (Platalea flavipes), glossy ibis (Plegadis falcinellus), nankeen night heron (Nycticorax caledonicus), Australian pelican (Pelecanus conspicillatus), intermediate egret (Ardea intermedia) and eastern great egret (Ardea modesta).

The glossy ibis is a colonial-nesting waterbird who forages in both terrestrial and aquatic habitats. This individual was photographed foraging at the Macquarie Marshes in October 2016. Image credit: Freya Robinson

Nankeen night herons nest in tall trees and prefer surface water for feeding. This individual was one of many nesting in tall River Red Gum trees within Barmah-Millewa Forest in November 2015. Image credit: Freya Robinson