BirdLife Australia will carry out the 2019 Aussie Backyard Bird Count during National Bird Week (October 21-27).

Residents can join people from all over the country to help count more than three million birds using the #AussieBirdCount app.

Register now at aussiebirdcount.org.au and discover the birds in your backyard.

BirdLife Australia is predicting a record-breaking count in one of Australia's largest citizen science projects.

"Spring is always an exciting time for bird watchers in Australia, not only because it brings an abundance of bird life but it also signals the return of the popular Aussie Backyard Bird Count," chief "bird nerd" Sean Dooley said.

"Australians will begin to see, and hear, a range of birds returning to their backyards over the coming months, making it the perfect time of year to count."

Spring also means the birth of many new birds - and data from the Aussie Backyard Bird Count will help BirdLife Australia keep an eye on bird populations across the country.

"The updated Aussie Bird Count app allows you to take part anywhere," a council spokesperson said.

"Not just backyards, but in local parks, botanical gardens, schoolyards or beaches - wherever you might see birds.

"The national total will be updated in real time, and the app allows you to see which species are being counted in your local area."

Start spreading the word with #AussieBirdCount.

For events and activities during National Bird Week, visit aussiebirdcount.org.au