PASSERIFORMES: Acanthizidae
Calamanthus campestris
This photo is a shocker and I will replace it as soon as I can (which sadly won't be anytime soon) but this is the only view I got of this skulking bird in several hours of looking.
Don't be fooled by nice clear photos of stuffed dead Rufous Fieldwrens placed out in the open and submitted by other photographers on the site ;)