Black netting has been applied to the callery pear trees on Leigh Street in a pilot program costing the Adelaide City Council about $15,000.

The move comes after months of exploring options to control the flocks of tree martins and nuisance and public health concerns.

City Services Director Tom McCready said about 10,000 birds regularly roosted in the trees from dusk and deposited large amounts of droppings.

“It’s reached the point where we need to do something,” McCready said.

“We have reduced the tree canopy through pruning to try and minimise the range of the birds on the street and keep them away from buildings.”

Other options had been considered and now netting was being trialled.

“After looking at other measures including removing the trees and sonar technology to deter the birds, we have decided to see if netting will divert them to another location in the city,” McCready said.

Leigh Street trees shelter the largest tree martin bird roost in Australia. Photo: Green Adelaide

The callery pear trees in Leigh Street were planted between 1997–2000 as part of a Renewal SA project to revitalise the street.

They are also found on Bank, Frome and Flinders streets.

Green Adelaide presiding member Chris Daniels said it was anticipated that the bird will relocate, potentially to trees on nearby Bank Street or North Terrace.

He said tree martins were a declining species and to have this population in the city’s heart “is incredible from a conservation perspective as well as being a much-loved spectacle for nature lovers and passers-by.”

“The work of Green Adelaide champions environmental outcomes amidst urbanisation and we appreciate the need to balance community expectations and environmental benefit,” Daniels said.

“The estimated 10,000 birds that congregate in Leigh Street is the largest anywhere in Australia – and having them right here in Adelaide’s CBD is a shining case for how our cities can be wild.”

The Coffee Branch on Leigh Street. Photo: Helen Karakulak/InDaily

Leon Glouftsis has owned the Coffee Branch on Leigh Street for six years and says the birds are a problem.

He said it was not just the droppings and smell, but shedding feathers also fell to the point that baristas had to shield coffees.

“We don’t even get the majority here because we’re at the quieter end of the street, but we still get the birds flying past,” he said.

“When we’re making coffee, pouring milk in and there’s feathers flying past, we can’t have that and feathers going in your coffee.

“It seems the feather problem is getting worse than what it was even five years ago, I don’t know why, maybe there are more birds.”

The trees are being netted ahead of the birds’ peak migration season between January and May. Photo: Helen Karakulak/InDaily

Glouftsis said the council previously cleaned the street three times daily during the bird migration season.

“You try and wash it, and that’s great and they did a good job of keeping it clean, but you wash it and the odour is in the concrete, in the paving and it regenerates,” he said.

“I remember when the guys were down there washing their areas with the pressure cleaners, I’d walk down to the bakery and it would be like when I was growing up on the farm and going in the chicken coop, it’s awful.”

“Look, if (netting) works it’s great because obviously you don’t want to chop the trees down unless you really, really have to because yeah, the trees are nice,” he said.

Daniels said that Green Adelaide “appreciate the situation that led to this pilot program, including public health concerns, and acknowledge that the City of Adelaide investigated several alternate options before landing on this trial”.

The behaviour and welfare of the tree martins will be monitored throughout the netting trial.