Parks Victoria is urging Wimmera residents not to illegally dump rubbish in conservation areas.
It follows a survey in Deep Lead, north of Stawell, that shows the numbers of a critically endangered species of bird appear to be recovering.
Surveyors sighted up to 100 Swift parrots in Deep Lead Conservation Reserve in the space of two days during a winter survey.
Parks Victoria's manager for science and management effectiveness, Dr Mark Antos, said the reserve was an active goldfield during the 1800s and was heavily dug over and disturbed.
"Since being protected in 1982, the native eucalypt woodlands have recovered and it is now a haven for wildlife," said he said.
"The reserve contains a vast range of eucalyptus species which provide a supply of nectar over much of the year for many native animals. This makes it a hot spot for birds affectionately nicknamed 'blossom nomads', such as purple-crowned lorikeets and rambunctious friarbirds, which travel together across the landscape searching for eucalypt blossoms."
Dr Antos said the survey also revealed the reserve still suffered the negative impacts of illegal rubbish dumping.
"We were sad to see how much rubbish had been dumped during our first survey in 2016, and the problem persists three years later," he said.
"This is one of the most important sites for nature conservation in Victoria, and deserves more respect. We need everyone to play a part in keeping it healthy."
A Parks Victoria spokeswoman said it was estimated there were only 2000 Swift parrots left in the wild, and that they were one of only two species of migratory parrot in the world.
She said the parrots bred in Tasmania and flew to the mainland in winter to feed on flowering eucalypts.
Parks was helped in its survey by citizen scientists group the Field Naturalists Club of Victoria.
Robin Drury, a member of FNCV's fauna survey group, said it had been visiting Deep Lead and other reserves between Stawell and the Grampians for four to five years.
"On our first trip up there, using hair tubes we discovered the presence of brush-tailed phascogales, which are also threatened," he said.
"They are a small mammal that uses tree hollows but also lives on the ground, and they seem to have a stronghold in the Ararat Hills Regional Park. In the times since we've put cameras out we haven't been able to take any pictures of them."
Mr Drury said the group was looking at doing another project with Parks Victoria and landowners in the Ararat area to see what the distribution was of phascogales.
While you're with us, you can now receive updates straight to your inbox twice weekly from the Wimmera Mail-Times. To make sure you're up-to-date with all the news from across the Wimmera, sign up below.