ONE of Scotland's most important and recognisable birds, the curlew, could become critically endangered, a new study has revealed.

Wading bird numbers have plummeted by 55% to 31,900 breeding pairs.

The survey, by the British Trust for Ornithology (BTO), is due to be released today at the 2013 Scottish Birdwatchers Conference in Edinburgh.

The study highlights the latest decline in numbers of Europe's largest wader, which have now reached near-critical levels.

The BTO fears it is only a matter of time before curlews are added to the UK Birds of Conservation Concern Red List for species at greatest risk of extinction.

Results from the surveys also showed that populations of lapwings, another key wading bird in Scotland, which is already red-listed in the UK, have dropped 48% to just under 44,000 breeding pairs.

Dr Chris Wernham, head of BTO Scotland, said the new evidence suggested current conservation management measures were still not enough to reverse the population declines of wading birds across Scotland.

She said: "This is very concerning, particularly for the curlew. It looks as though the curlew is going to have to go on to the red list for endangered species [as well as the lapwing]."

The RSPB echoed fears for wading birds.