Two of the baby birds flew away, but one fell to the ground.
Fauna relocator Allison Dixon will hand rear the bird that could not fly, but fears the other fledglings will die slow and agonising deaths.
Ms Dixon despaired at the ‘nonchalant’ process for clearing trees.
‘This was in a tree preservation area,’ she said.
‘After the chainsaw cut through the hollow, the fledgling fell about 6m.
‘He was just two to three weeks away from leaving the nest.’
Ms Dixon said residents had approached her complaining about the way trees were cleared with wildlife still inside.
She urged anyone cutting trees to consider the fact it was nesting time.
‘Just give the birds a chance,’ she said. ‘Leave it a few weeks, how hard is that?’
A City of Mandurah spokeswoman said the tree on Lot 2, Indoon Place was assessed by aboriculturalists and found to be dying.
‘If left to deteriorate further, the tree would become a safety hazard,’ she said.
‘Although the tree was in a tree preservation area, it was found to be in a poor and potentially dangerous condition, so was exempt from planning approval requirements.
‘The landowner therefore had the final decision to remove the tree.
‘It is the responsibility of the arbourist contracted to remove the tree to complete a fauna assessment and contact fauna relocators if necessary.’