OATLEY resident Vicki Bolling will take part in the Aussie Backyard Bird Count to learn what types of birds are flocking to her yard.
The event relies on "citizen scientists" spending 20 minutes to document the bird species in their yard or a nearby park. The information is used to map bird habitats and numbers.
Ms Bolling, who has a general interest in native wildlife, recently spotted a variety of birds in her yard and Oatley Park.
As well as butcherbirds and crimson rosellas, she spotted a flock of yellow-tailed black cockatoos.
"It is pretty amazing when you get something like that in Oatley," she said.
"It is nice to be aware of the birds that are around and to see the changes: the birds you now see compared to the birds you used to see.
"In my yard I don't see the wattlebirds that I used to see, which is a shame.
"I also don't get as many crimson rosellas.
"They seem to have been superseded by rainbow lorikeets."
The amateur bushwalker said going on walks with members of Oatley Flora & Fauna Conservation Society had helped her identify different species of birds.
Ms Bolling encouraged other residents to take part in the event.
"It doesn't take very long — you don't have to go anywhere, you can just notice what's in your yard one day."
The Aussie Backyard Bird Count ends this week.
Details: aussiebirdcount.org.au