Many thanks to Steve Davidson who located the Stilt Sandpiper and pointed it out to us.
Stilt Sandpipers are rare vagrants to Australia with only three previously confirmed sightings.
I found it difficult to distinguish the Stilt Sandpiper from the Curlew Sandpipers at first but after studying it for a while came up with the following points:
1) The Stilt Sandpiper is slightly bigger and more solid looking than the Curlew Sandpiper.
2) The Stilt Sandpiper's legs are skinnier with the knee joints relatively further from the body.
3) The Stilt Sandpiper is significantly darker looking on the breast with markings continuing down the flanks.
4) The bill looks more solid than the curlew sandpiper's, the tip heavier and the downward curve not as pronounced.
5) The Stilt Sandpiper's legs are lighter in colour (yellowish) but this was only clear when the bird didn't have them immersed and the light was good.