This is the finding of Adrian Davis, a University of Sydney biological sciences graduate who is working on a thesis for his doctorate of philosophy (PhD).

In the pilot study, Mr Davis has confirmed the existence of a higher density of parrots in the city than in national parks, such as the Royal National Park, where he did part of his research.

Mr Davis is wondering whether the ``increased frequency of fires and droughts resulting from climate change'' will drive parrots to the city.

"Hopefully, after putting lots of cameras in lots of trees, I'll have the answer,'' he said.

Mr Davis wants to find out why there are now greater numbers of certain species of parrots living in Australian cities.

Mr Davis believes easier access to food and water sources in urban areas is a contributing factor.

He says the aggressive nature of rainbow lorikeets and sulphur-crested cockatoos may become more prevalent and play a part in the disappearance from some areas of animals such as owls or possums.

Mr Davis climbed five eucalypt trees up to 20 metres high in the Royal National Park and placed motion-activated video cameras opposite tree hollows at the start of the mating season last August.

Each camera, which has night vision, has an infra-red sensor to record when something moves.

Mr Davis said many of these cameras would be used in the next study in August.

Have you seen more parrots around this year?