Stevehapp, a member of the Birds in Backyards forum identified the bird for me.
It wasn't moving around too much and just changed trees a few times, allowing me to snap it as many times as I wanted. The bird has a strong bill with a hook at the end of the upper bill.
For a bird that doesn't look very special, it surely has an unusual habit of dealing with its prey. It kills insects, small birds, reptiles and mammals for food. And when the prey is too large to swallow in a go or for later consumption, the bird will hang the prey on thorns or in the fork of a branch like butchers hang meat. Nasty.
Photos taken: 20/10/2009
OzAnimals.com - Grey Butcher Bird
Birds in Backyards - Grey butcherbird
Guide to the wildlife of the Perth region (Simon Nevill Publications)