John Wood, Max Gillies and Benita Collings co-signed a letter that was sent to mayor Peta Pinson.

The actors were in Port Macquarie as cast of Senior Moments during March.

In the letter, the actors say that two cast members witnessed a Rainbow Lorikeet and a Scaly Breasted Lorikeet collide with the entertainment complex.

"It was several metres above the ground. Both birds fell to the ground, stunned and unable to move," the letter says.

"The Scaly Breasted Lorikeet was in a particularly bad way, and blood and lost feathers were evident on both birds.

"We were able to collect and contain the birds - the Rainbow Lorikeet recovered relatively quickly and was able to be released - the Scaly Breasted Lorikeet, on the other hand, was taken to FAWNA (For Australian Wildlife Needing Aid) wildlife rehabilitator, where it recuperated overnight and was then released.

"While in this instance the injured birds had a happy outcome, we were dismayed to learn that bird collisions with the Glasshouse are a regular occurrence."

But Port Macquarie-Hastings Council says it is very rare for bird collisions with the Glasshouse.

"We are not aware that this (bird strikes) have happened since 2013," a spokesperson said.

"If it did occur, we would certainly contact FAWNA."

FAWNA's Meredith Ryan says it attempted to address the issue with council a number of years ago but was unsuccessful.

"Council is mistaken if it believes bird strikes are a rare event at the Glasshouse," she added.

The letter says that the actors were "informed by venue staff, FAWNA and other locals, that collisions happen weekly - often in large numbers and with fatal consequences".

The actors said the FAWNA bird rehabilitator acknowledged that sometimes a whole flock of Lorikeets fly directly into the glass (seeing only reflected sky and trees) with many birds killed on impact.

"Already stretched FAWNA volunteers are left to collect, rehabilitate and, sadly, often euthanase native bird life on a weekly basis. Untold numbers of birds who manage to fly off on their own after impact will die later from untreated injuries," the letter continues.

"We've been informed by FAWNA that council do not monitor or keep a record of bird collisions. In addition, there are apparently no steps being taken to address the issue.

"Surely a venue that advertises itself as "environmentally sustainable" should be concerned about the negative impact it is having on wildlife?

"Billions of birds die from glass collision globally per year. Aside from habitat destruction, it is the biggest human related killer of birds worldwide. Place a large glass building in an area full of thriving bird life and you have a recipe for disaster.

"Awareness of these consequences has grown, however, and new technologies in glass manufacture and treatment are becoming more available."

The actors said steps can be taken to minimise the incidence of bird collision, such as using UV treated glass, adhering external anti-reflective film to the glass, frosting or etching the glass, applying horizontal or vertical lines, screening the glass externally and more.

Many of these solutions can be retrofitted to existing buildings, they said.

"The Glasshouse attracts high profile performers, artists and events from around the country and beyond. It is an artistic and cultural hub for the greater Port Macquarie-Hastings community.

"It sits in the very heart of Port Macquarie, between the river, the wetlands and the sea. This beautiful area has been home to native bird life for millions of years and the natural splendour of Port Macquarie is valued by tourists and locals alike.

"The Glasshouse however, has been described unprompted by locals as "the building that all the birds crash into." On the 10th Anniversary of the Glasshouse, is the council really happy to have that as the building's legacy?"

The actors' letter calls for immediate action including, research into how to reduce the incidence of Glasshouse bird collisions, Glasshouse staff be inducted into bird rescue procedure, provision of gloves and a securable box to house injured birds and that records be kept of all bird collisions.

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