(AU) Decline In 'Successful' Bird Species Like Magpies And Kookaburras Rings Alarm Bells

ABC Central West - Micaela Hambrett

Typically a bird that does well in built-up areas, the decline in magpie numbers across the country has shocked experts. (Supplied: David Flannery)

Key points BirdLife Australia is concerned magpie and kookaburra numbers are declining Theories include the use of second-generation rodenticides, changing agricultural practices, climate change and more frequent droughts One positive, though, is coronavirus shutdowns mean more people may be free to participate in the annual Birds in Backyard survey this year

Sean Dooley describes magpies as being one of the few native bird success stories of European settlement.

So when dwindling observations were recorded across 15 years of Birdlife Australia surveys, alarms bells started ringing.

Mr Dooley, BirdLife Australia's national public affairs manager, said magpies were "open grassland and woodland birds".

"With agricultural and urban areas we've actually created pretty amenable habitat for them in that there's a lot of open space with scattered trees so they can nest in, roost in and survive in the landscape," he said.

But BirdLife Australia data shows that Australian magpies declined by 31 per cent in the East Coast region — including Sydney and Brisbane — between 1998 and 2013.

"They declined by roughly 20 per cent in the South East Mainland Region, which includes Melbourne, Canberra and Adelaide [for the same period]," Mr Dooley said.

The data also reflected a dramatic decline in kookaburras and birds of prey, suggesting carnivores were potentially more vulnerable to these unknown environmental changes.

Kookaburra numbers have declined by up to 40 per cent on the east coast of Australia. (Supplied: David Flannery)

Agriculture, climate change and drought

One possible theory was that the use of second-generation rodenticides was having a bigger toll on birds through secondary poisoning.

"Birds like boobook owls, other birds of prey, and magpies are actually eating rats that have been affected by the poison and it can actually kill them, whereas the earlier rodenticides didn't seem to affect the birds as much." Mr Dooley explained.

Other factors the group was considering included changing agriculture practices, climate change and more frequent droughts.

Although this did not mean magpies or kookaburras were endangered yet, it did indicate food and habitat conditions were under serious pressure.

"It's a huge wake-up call. If these really successful birds are starting to suffer, something's going on in the environment," Mr Dooley said.

With the next report due out next year, he said he expected the downward trend to continue.

"The additional five years [since the last report] have just been more drought conditions. I can't imagine things would be bouncing back," he said.

Largest natural history data set

BirdLife Australia's data is critical to painting a large scale, real-time picture of Australia's bird populations providing insight to researchers and academics.

BirdLife Australia's Sean Dooley hopes unique insights into backyard birds will emerge from the coronavirus lockdown. (Supplied: BirdLife Australia)

The data that made up these reports was nearly all gathered by volunteers.

"We have literally thousands of people sending in tens of thousands of surveys every year. It's probably the biggest citizen science project in Australia and one of the biggest natural history data sets in the country," Mr Dooley said.

Urban and suburban observational data was critical to "filling in the gaps" for common birds that share our spaces, as birdwatchers typically head to more pristine environments seeking rarer species.

Although an entry level survey, Mr Dooley said backyard bird observational data had been able to reflect nuanced trends, such as population decline between regional and metro areas indicating widespread environmental degradation.

Take cover! A young cyclist takes evasive action as a magpie swoops in Casino, New South Wales. (ABC Open contributor Dee Hartin)

This year, the coronavirus lockdown has coincided with the organisation's annual autumn Birds in Backyard survey and it might provide an accidental boon for BirdLife's data sets.

"One bit of positivity is with everybody at home, if we can get them to do their surveys, we're going to get a huge boost in our knowledge of what birds are using urban, suburban and town areas," Mr Dooley said.

Links

• Climate Change Is Pushing Bird Boundaries, Community Scientists Confirm
• (AU) Birds are the “canaries in the climate-change coal mine”
• (AU) Birds threatened by rapid climate change
• Rising temperatures could make some U.S. state birds ‘stateless’
• Climate change isn't just shifting how the world feels, it's changing how it sounds
• Decline in 'successful' bird species like magpies and kookaburras rings alarm bells
• Climate change is causing birds to shrink, study suggests
• Population responses of bird populations to climate change on two continents vary with species’ ecological traits but not with direction of change in climate suitability