The Australian government’s new multi-billion national broadband network has found itself under attack as parrots chew through its cables.

Australia’s average internet speed is 11.1MBps, making it the 50th fastest in the world. A major infrastructure project, which aims to roll out better service nationwide, is due to be completed in 2021, although it is already attracting criticism for slow speeds.

Engineers visiting sites to check on the cables have found them damaged, having been chewed by cockatoos. Most of the damage has occurred in southeast Australia in areas surrounding grain farms, which attract the birds.

According to the National Broadband Network (NBN) Company, the network builder, repairing the damage done by the birds has already cost $80,000. These costs are likely to rise as further bird-inflicted damage is revealed.

NBN is planning to cover the cables with inexpensive, protective plastic casing to protect them from birds and other animals in the future.

“They are constantly sharpening their beaks and as a result will attack and tear apart anything they come across,” said Chedryian Bresland, co-project manager at NBN, in a blog post. “Unfortunately, they’ve developed a liking to our cables […] these birds are unstoppable when in a swarm.”

“We’ve been going back to our sites and discovering all this damage on the spare cables we had been hoping to use on our towers. They were damaged to the point of not being repairable, which has forced us to rip out the whole lot and completely re-run new fibre and power cables. That costs us about $10,000 every time we have to do that.”

Cockatoos are highly social and intelligent birds capable of learning to speak, although in some areas they are considered pests. They are known for attempting to eat anything from their standard diet of fruit, nuts, vegetables and seeds to bits of buildings and have even chewed through steel braiding to get through to cables.

“It would have to be an acquired taste, because it’s not their usual style,” Professor Gisela Kaplan, an animal behaviour expert at the University of New England, said to Reuters. “Cockatoos usually go for wood or strip the bark off trees. They don’t usually go for cables, but it might be the colour or the position of the cables that’s attracted them.”