Patricia Gill, Denmark Bulletin

Denmark school students are part of a landscape-scale move to re-establish the breeding of black cockatoos in the region.

To spark their students’ enthusiasm, environmentalist Simon Cherriman visited four schools recently and helped the students build four nesting boxes at each school from recycled materials.

One nesting box was installed in each of the school grounds and will form part of a cockatoo refuge.

The students will also pick seed with WICC’s revegetation officer and plant this around each school nest box so each school has a cockatoo sanctuary.

The Wilson Inlet Catchment Committee-run project aims to install 44 nesting boxes across the catchment with 90 landholders putting up their hands to host the boxes.

The three-year project is funded in part by the WA State Natural Resource Management Program. Also farmers will host the planting of 20ha of ‘cockatoo flora’, such a banksias and hakeas, with 20km of fencing to be installed to protect priority remnant vegetation.

But with 60 per cent of the catchment now cleared for agriculture the cockatoos’ nesting hollows and food sources are under threat. Simon visited Kwoorabup Nature, Golden Hill Steiner and Denmark Primary schools, and Mt Barker Community College to spread his message.

It is too late to replace the former giant trees with nesting hollows and the birds’ sources of food, so the next generation of cockatoo custodians are learning how to build on protecting the cockatoos.

A bird-watcher since childhood, Simon grew up making nesting boxes for animals and likened the biodiversity to a human body.

“If it’s all there, it’s healthy, and if you lose one of those bits you might not die but you’re not going to be as healthy as before,” he said.

“If you lose your eyes you’ll go blind, and you may not as healthy as before.

“But if you begin to lose bits and pieces, eventually your body does not work and that’s your life gone.

“The country we live on is the same: there’s all these parts and it’s healthiest when biodiversity is there.

“If we lose a species that (country) is not as healthy as it used to be, and that species might not even be noticed.

“But if we lose too many species – all of those species (that are lost) have a vital role to play in keeping country healthy.”

A major part of this biodiversity is trees – marris, jarrahs and karris – which form hollows over hundreds of years.

As trees grow the hollows may expand creating pipes and chimneys with one tree hosting many ‘hotels’ for possoms, phascogales, bats, carpet snake, parrots, pardalotes, owls and boobooks, etc.

These need a ‘window’, corridor and living space – a well-drained protected cavity for creatures to live in.

A tree such as an ancient jarrah can be full of living creatures in their hollows – birds, reptile and insects – up to 800 types of insects alone.

The project focuses on three different types of cockatoos – Baudins, with a long upper beak, Carnabys, which has shorter upper beak, and red-tailed cockatoos.

Carnabys cockatoos move seasonally in big flocks to where there is water, inland for breeding and back to coast with their chicks.

“They move in flocks of hundreds whereas once they moved in thousands because the whole of WA’s inland was covered in forest,” Simon said.

“I feel like it’s the country taking a big breath in of cockatoos as they contract to the inland areas.

“In the non-breeding season country breathes out.”

Baudins cockatoos move north when not breeding and south to breed while red-tailed cockatoos, karraks, stay in their family groups and don’t move anywhere over their lives.

Black-tailed cockatoos can live up to 50 years, are found only in the South-West, have one offspring a nesting and spend years rearing their offspring.

“Historically, they had all this land to move back and forth but Europeans changed this markedly and now we’ve lost 90 per of where Carnabys cockatoos used to go to breed,” Simon said.

The Denmark Men’s Shed will build 40 nest boxes which will be installed at priority properties by Ecological Tree Services.

Seeds have been picked in collaboration with Southern Aboriginal Corporation’s rangers to plant out at least 20ha of cockatoo foraging flora.

See all the photos in the issue.

This article appeared in the Denmark Bulletin, 21 March 2024.