Mistletoe decline could threaten nectar-feeding bird populations

The regent honeyeater often relies on mistletoe nectar, fruit and foliage during drought. (Supplied: Lachlan Hall)

Ecologists fear the widespread loss of native mistletoe due to drought could leave nectar-feeding birds even more vulnerable.

Charles Sturt University ecology professor David Watson said birds relied on mistletoe nectar, fruit and foliage during drought.

But researchers recently discovered a concerning decline in the shrub while monitoring nectar-feeding birds at 2,000 sites across south-eastern Australia.

"(We) found that during the height of the drought, when it was not just really dry, but critically also quite warm at night, almost all mistletoes died," Professor Watson said.

David Watson says mistletoe becomes a vital source of food for birds during drought. (Supplied: Charles Sturt University )

Misconceptions about mistletoe

There are almost 100 species of mistletoe in Australia.

Professor Watson said there was a misconception that mistletoe was a pest, due to its parasitic nature.

"And when it's very dry and crispy and plants are struggling to get enough water to survive, mistletoes don't care, they just slurp water out of the tree."

Birds including the critically-endangered regent honeyeater rely on mistletoe. (Supplied: Mick Roderick )

Professor Watson was a co-author of a report on the decline that was led by Australian National University's Difficult Birds Research Group member Ross Crates.

Birdlife Australia national public affairs manager Sean Dooley said the study's discoveries didn't come as a surprise.

He said the critically-endangered regent honeyeater was among the most vulnerable nectar-feeding birds.

"Saving these birds is important not just because they're wonderful birds, but they're also part of of our woodland ecosystem and are really important pollinators," he said.

"We need them to keep our forests healthy."

Threats to survival

Mr Dooley said woodland bird populations were declining across south-east Australia due to historical and ongoing land clearing.

"We need to preserve what we have left, and often the best areas of woodland are remnants on private land," he said.

He said work needed to be done to protect and enhance woodland on public and private property.

Sean Dooley says nectar-feeding birds were already vulnerable. (Supplied)

Mr Watson said something needed to change urgently before it was too late.

"If we keep pushing the lever of climate change just a little further, things are going to start succumbing," he said.