AN UNPRECEDENTED investigation of Victoria's bird life has found it is collapsing, with two out of three woodland species in significant decline.
The 12-year research into native species found that generations of land clearing and more than a decade of drought linked to climate change has reduced numbers for more than 80 species.
Those affected include the laughing kookaburra and species of honeyeaters, thornbills and lorikeets.
Deakin University ecologist Andrew Bennett said he was cautious about blaming climate change, but the decline in the state's centre and north might be ''what we have to get used to''.
''Clearly it shows when we have sustained change in rainfall and sustained change in climate it is having a marked effect,'' he said.
''In this case it is on birds. What is concerning is that we don't know what's happening to other groups - to reptiles, to mammals, to invertebrates.''
Professor Bennett said that the report underlined the need for systematic monitoring of wildlife.
''When we have a financial crisis we put vast resources into it. But we have a biodiversity crisis and nothing happens,'' he said.
''There is some good restoration and revegetation by landcare groups and others but the scale of what we're doing doesn't match the scale of the problem.''
A State Government report last year warned Victoria has the most devastated landscape in the country.
More than half of all native vegetation and 80 per cent of private land has been cleared since European settlement.
A land and biodiversity white paper explaining how the Government plans to tackle the crisis is due before the end of the year.
The bird research, published in the journal Diversity and Distributions, brings together the results from three long-term studies surveying across 30,000 square kilometres.
It found the fall in numbers was as great in remaining woodland areas as in cleared landscapes, suggesting that current reserve systems alone were not enough for species to survive as the climate changed.
The decline was most dramatic over the past five years as food shortages increased and breeding nosedived. Professor Bennett said red ironbark trees - a major food source for nectar-feeding birds - had hardly flowered in five of the past eight years.
''One of the things that concerned us is that it's not just threatened species that have declined, but also some of the common species like laughing kookaburras, red wattlebirds and grey shrike-thrush,'' he said.
Victoria Naturally Alliance, a collection of eight environment groups, said the state was facing an ''extinction crisis''.
CSIRO has reported that 30 per cent of the state's animals and nearly half its plant species were threatened or already extinct.
''There is a critical need to improve the quality of existing habitats and restore habitats, especially in more fertile areas adjacent to existing bushlands,'' alliance spokeswoman Karen Alexander said.