Canberra's urban areas risk becoming as dirty as London's Trafalgar Square if people don't keep their bread to themselves.
"Don't feed the birds," people are being told, with the reminder "what goes in must come out".
A tongue-in-cheek video made by the ACT Government and posted to Facebook has already garnered thousands of views.
The video came with a serious message even though it was shot and edited like an Alfred Hitchcock thriller.
"It can be really tempting to feed birds but just remember what goes in must come out," Territory and Municipal Services' Mal Gale said in the video.
"Human food, like bread, is bad for birds' digestive systems. They begin to see humans as a food source, which can increase their numbers in urban areas significantly and the chance of disease spreading climbs.
"If you've ever been to Trafalgar Square you'll know what we're talking about.
"Let's keep the bush capital beautiful."
One woman, Elaine Stanford, wrote on the government's Facebook she had seen many bird feeders in Garema Place and that no one could see the signs on the sides of the garbage bins.
"Today (like every other day) .... along came the many bird feeders (there are so many who turn up)," she wrote.
"Maybe the rangers could educate the bird feeders for a week or place the signs where they can be seen?"
John Garvey wrote: "Last Sunday at Yerrabi Pond a mother and her young child turned up with two loaves of bread and started feeding the water birds. You need large signs at these places in multiple languages."
Another said: "Whoever is making these ACT Government videos deserves an Oscar. Bravo."
Feeding birds was banned in Trafalgar Square more than a decade ago, but it has not stopped animal welfare protesters feeding them.
Feeding birds is not illegal in the ACT nor is it encouraged. While it was government policy not to feed them, people could not be fined for doing it.
TAMS' manager of places Jane Carder said bird populations were increasing at Garema Place and Tuggeranong.
Rangers had spent hours cleaning out birds nests and poo several centimetres thick from underpasses, and installing bird barriers in Tuggeranong.
She said public seats in Garema Place were dirtied by birds not long after being cleaned.
"It's really hit and miss when you walk through that area," she said.
The pigeon population in Garema Place was growing along with magpies while elsewhere in the ACT swamp hens and seagulls ate food thrown by people.