No one knows the true status of an endangered finch that's delayed the Adani coal mine, including the Queensland government, experts say.
Researchers have reviewed contemporary studies on the black-throated finch and say there are big knowledge gaps on how many are left, exactly where they are living, and how far they roam.
They warn that uncertainty about distribution means knowledge of the bird's optimal habitat is likely to be "biased or incomplete".
They also point to limited outcomes from a national recovery plan for the species.
The finch is known to inhabit Adani's controversial Carmichael mine site, in Queensland's Galilee Basin.
Earlier this month the state government rejected Adani's plan to protect the bird, saying it was deficient. The company was told to go back to the drawing board and come back with a better plan if it wants its mine to proceed.
But it's now apparent that Adani's plan is not the only deficiency hurting the bird's prospects of recovery.
Researchers, including experts from the CSIRO and three Australian universities, say their review of finch studies and data means no-one knows the true situation.
They point to evidence of an alarming decline, primarily due to habitat loss, with the bird's historical range contracting by 80 per cent in the 1980s and 1990s.
There are two known remaining strongholds: the Townsville coastal plain and the Desert Uplands bioregion where Adani's mine, and other mining projects, are situated.
But they say scarce information about the bird's ecology has hindered effective conservation planning.
"There is a shortage of information on the present population size and distribution of the subspecies, which creates uncertainty about its conservation status," they write in a paper published in the journal Emu - Austral Ornithology.
"The current partial understanding of many aspects of the (finch's) ecology could lead to inefficient allocation of resources, or even result in perverse conservation outcomes."
They list a range of research priorities to get an accurate picture of what they call an "inconspicuous" species, including population monitoring in the two strongholds.
The authors say a national recovery plan for the finch was completed in 2007, but note "few conservation gains have been achieved 11 years after the initial plan, and there is still much uncertainty around the state of knowledge of the (finch) or best management guidelines".
The review involved experts from the CSIRO, James Cook University, the University of Queensland, the University of Melbourne, the federal government's National Environmental Science Program, and the Threatened Species Recovery Hub, which is partially funded by the federal government.
Australian Associated Press