Erin Ash was excited that the marsupial had chosen the tree in her front yard.

‘‘This was the first time I have seen one here in 26 years,’’ Mrs Ash said.

‘‘I wanted to cut this tree down because branches would always fall on my car but now I think it will stay for good.’’

Neighbour Bronwyn Jeffree was told about the koala after friends spotted it when they drove past.

Mrs Jeffree said a koala could be a sign that other colonies may be scattered around the bushland corridor and believes it is a good reason not to go ahead with the Gandangara development plans.

‘‘I would rather have koalas than 5000 new houses any day,’’ she said.

‘‘This might make people have a think about the real effect of using pristine bushland for making money.’’

Dr Robert Close and his University of Western Sydney students have been studying koalas since 1990.

They had found tagged animals from the Wedderburn colony near Campbelltown at Alfords Point and Heathcote National Park.

‘‘Koalas can disperse 20 kilometres and usually head across Heathcote Road into the suburbs,’’ he said.

‘‘My prediction is that we are going to see more of them pop up along this road and wander around.’’

Dr Close said this untagged koala could have been from Campbelltown, Holsworthy, or was just a sign of wider increased breeding.

The Christmas bushfires in 2001 destroyed much of the koala habitat in Heathcote National Park.

Sutherland Shire Council national areas manager Brendan Graham said the animal would probably stay in the tree for a while.

‘‘When it decides to move it will be at night when there are no cars or dogs nearby,’’ Mr Graham said.

‘‘If anyone finds one they should just leave it alone, as they will move on by themselves when they are ready.’’

Have you seen any koalas near where you live?