Quokkas are small marsupials native to a small corner of south-western Australia and considered endangered.
The local population around Northcliffe had been badly hit by a massive bushfire in 2015.
The World Wildlife Fund (WWF) conducted a survey 12 months after the blaze and estimated there were only 39 quokkas left in the fire zone area.
But a recent routine inspection of remote sensor cameras picked up multiple sightings of a young quokka joey along with its mother and another adult.
The video is a sign of population recovery that brings hope for the species, said WWF Australia Species Conservation Manager Merril Halley.
"The two adult quokkas were both survivors of the intense blaze so we were all thrilled to see a joey," she said.
"The mother and an adult male quokka also seem to be on very good terms and have been seen together consistently for the past six months.
"It is unusual to see male-female interaction over a period of time as long as this, so this is really interesting for us."
The Northcliffe fire burned some 98,000 hectares, making it the biggest bushfire in Western Australia since 1960.
Ms Halley said it would take a long time for the quokka habitat to fully recover. Even though bush is slowly regrowing, tree canopy regeneration takes more time.
"With such a small number of quokkas left in the region, it's vital that we are out there protecting these animals," she said.
The discovery of a baby quokka in a fire-hit area of Western Australian has given hope to conservationists.