Mystery bird, Australian National Botanic Gardens, Canberra

What is this bird?

During my visit to the Australian National Botanic Gardens in Canberra early this year I saw the bird shown in the photograph above.

Even though it is a reasonable photo, I am at a loss to determine the species. It was  not happy with me being there taking a series of photos.  I heard several others but they failed to show themselves. The photo was taken in the fern gully near the entrance to the gardens. Below I’ve included several more photos of the habitat.

At first I thought they were White-browed Scrubwrens, but the call was wrong and there is no prominent white eye-brow.

The closest I can come to identification is Large-billed Scrubwren, but that species is not listed on the bird list for the gardens. Birds Australia atlas site is no help either.

Can any one help me? Leave your suggestions in the comments, or use the contact form.

UPDATE: I put out a request on the Birding-Aus and Canberra Birds newsgroups yesterday asking for help with identification of this bird. I had about 15 people reply and all but one said it was a juvenile White-browed Scrubwren. The mystery has been solved. Thanks everyone. I’ve published some pertinent responses in the comments below.

Fern gully, Australian National Botanic Gardens, Canberra

Ferns in the Australian National Botanic Gardens, Canberra