David is correct. Although that on balance of
probability, it is more likely to be a Blackbird, does not entirely rule out the
possibility of it being a Bassian Thrush instead. We do rarely get the Bassian
Thrush in Canberra gardens (not just ANBG). Specifically, there were 11 GBS
records within the first 21 years of the GBS, all between December and
June. However you wrote "I did not get a good view of the patterning on its
breast" so it would be very hard to be convincing either way. Another point is
from that there are four far more relevant books, than is Pizzey & Knight,
available on birds of Canberra. These give far better (more local
knowledge) on which you can get data of the status (and in one case
something on the identification of our birds).
Taylor, M. & Canberra Ornithologists Group
1992, Birds of the ACT: an Atlas. Canberra Ornithologists Group and
National Capital Planning Authority, Canberra.
Taylor, M. & Day, N. 1993, Field Guide to
the Birds of the ACT. National Parks Association of the ACT, Canberra.
Veerman, P. A. 2003, Canberra Birds: A Report
on the first 21 years of the Garden Bird Survey. Philip Veerman,
Wilson, S. 1999, Birds of the ACT: two centuries
of change. Canberra Ornithologists Group, Canberra.