The number of some of Australia's iconic birds, which includes the kookaburra, magpie and the willie wagtail, is on the decline, according to a report released on Wednesday.

Volunteers from Birdlife Australia have compiled data from among 420,000 surveys done since 1998, where it showed that the magpie, which is one of the most popularly sighted birds in Australia, is slowly declining in the east coast. Kookaburra and willie wagtail sightings, on the other hand, have been declining in the southeast.

Their discovery also revealed "significant decline" among birds of prey in the Australian outback, which includes owls, eagles and falcons. At least 22 species out of 39 in the Malle region in the southern part of Australia are also dwindling in numbers. Many other bird life populations in Melbourne, Adelaide and Canberra are also heading in a downward trajectory, according to The Guardian.

"You may see a bird such as a magpie wherever you go, so it may not make a lot of sense to people to say that it's declining in some regions. But it's not always obvious to a local observer that we are losing these birds in some places," said James O'Connor, the head of the research.

"It just goes to show you the value of large-scale, broad-scale systemized surveys because if you were relying on the anecdotal evidence of bird watchers and other people, they'd be saying that, 'no, of course magpies are still common,'" said Sean Dooley, the editor of Australian Birdlife, according to Tribune International.

O'Connor said much work will still be needed to determine what is causing the declines. "The next step is to fund out the drivers, which are likely to be habitat clearance, the intensification of agriculture, changed fire regimes and possibly climate change contributing to more extreme weather conditions. For carnivorous birds in arid regions, it may be environmental toxins," he told The Guardian.

The researchers hope the study will be able to, "motivate people to get out there and do this bird monitoring activity."

In response, Environment Minister Greg Hunt said that the government is putting efforts to save some 20 bird species in the next five years. "I want to bring these birds back far enough from the brink to survive. I want future generations to enjoy the color, movement and song they bring to our lives," Hunt said, according to Courier Mail.

Ten species have already been identified by the minister as "priority action:" the helmeted honeyeater, hooded plover, eastern bristlebird, regent honeyeater, mallee emu-wren, plains-wanderer, night parrot, Alligator Rivers yellow chat, Norfolk Island's green parrot and boobook owl.