It has already been brought back from near-extinction once, but conservationists are warning the corncrake's future could depend on ministers transferring £85 million of European money from farming to environmental schemes.

The Scottish Government consultation into the amount of funding available for agri-environment schemes opens this week, as alarming new information is released about one of Scotland's rarest breeding birds

The 2013 counts of ­corncrakes, an elusive farmland bird, revealed a 23% decline in the number of singing males to 971 from 1260 the previous year.

RSPB Scotland said the drop in numbers also demonstrated the precarious and vulnerable nature of the species and underlined how important agri-environment schemes were to help maintain a healthy population.

Vicki Swales, RSPB Scotland Head of Land Use Policy said agri-environment schemes were paid from the Common Agricultural Policy (CAP) funds - but still received only a small share of the total pot of money. The Scottish Government now had the option to allocate CAP funds in a different way that allowed for an increase in funding for agri-environment schemes.

She said the RSPB was calling on ministers to make this important decision and transfer the full amount of funds possible, a total of 15% or around £85m per annum.