We have had a number of galahs near our house over the last 3
years that have ringbarked the largest mallee tree on our 5 acre block. They did
it just below a hollow they had been investigating and enlarging. No evidence of
nesting in the hollow though.
This has resulted in the top two thirds of the tree dying; it is now
sprouting profusely from below the ring bark. It was is a shame to see this tree
with many dead limbs as this was probably our oldest tree too; from the size of
the trunk and the base it must be 60 - 80 years old (maybe more).