Owl attack risk forces relocation of Mt Coot-tha zip line project

Developers of a zip line through Brisbane's Mt Coot-tha Reserve have revealed that they have shifted the location of the operation to minimise the risk of attack from owls that nest nearby.

Late last year, Brisbane City Council approved a development application for the project from Zipline Australia, with Lord Mayor Graham Quirk having been an enthusiastic backer the nature-based tourism plan.

However, earlier this week a meeting at the Mt Coot-tha Botanic Gardens auditorium heard objectors raise concerns with both the project and the Council approval process.

Zipline Australia's own exhaustive development application revealed the position of the zip line had been moved to mitigate the risk of attacks by Powerful owls

Powerful owls have nested in parts of the Mount Coot-tha Reserve for at least 30 years, and conservation groups - including Birds Queensland and Birdlife Australia - had raised concerns about risks to the species and potential owl attacks on patrons of the zipline.

This led to a change of plans, with the tree-top walk moved 100 metres from the owls' nesting tree, the distance considered as an effective means of minimising attacks.

However, Birdlife Australia powerful owl project officer Dr Beth Mott advised that “some residual risk remains.”

Zipline Australia's assessment identified that "defensive owl behaviour" was most likely to be exhibited between August and November because of nestling and fledgling phases.

It said Zipline Australia staff would be trained to monitor the behaviour of powerful owls and other forest raptors to "minimise potential for attacks and disturbance".

Birdlife Australia raised a risk of abandonment and that the stress from zipliners and increased visitation might disturb the owls enough that they stop breeding.

Zipline Australia says they will introduce new nest boxes suitable for Powerful Owls (or their prey) along Mount Coot-tha

Acoustic experts think patrons will be having lots of fun, or be quite terrified, for up to a third of the ride.

Acoustic engineers say patrons are likely to be laughing/yelling for up to 30% of the 2.5 minute zipline ride.

The experts also think the zipline will create about 70 decibels of noise per metre - about the same as standing 15 metres away from a freeway.

Acoustic estimates of the noise generated by the zipline took into account an estimate of travel velocity of up to 60 kilometres per hour.

Dr Mott added “they've done the best that they can in allowing what is a fairly green business development to go ahead.

"It should provide excellent opportunities to actually allow the public to learn more about our wildlife and to value our green spaces."

Staff working on the zip line will be trained to identify what the report called "aggressive owl behaviour".

Images: A powerful owl (top) and artists impression of proposed zipline project (middle and below). Courtesy of Brisbane City Council.