Conservationists are embarking on an urgent mission to save one of the UK\'s most threatened birds from extinction. The three-year project, led by the RSPB, will aim to reverse a decline in the population of the farmland birds; the species is deemed the most likely bird to be extinct in the UK by 2020. The turtle dove population fell by more than 90% between 1997 and 2010. Part of the project will aim to restore plants that the birds feed on to the countryside. The birds\' diet consists almost entirely of small seeds from wild plants, which grow among crops. Changes in farming practices in recent decades mean these wild flowers - including vetch, fumitory and clover - are now scarce. As part of the project, the team will work with farmers to plant these seeds on their land. RSPB spokeswoman Heather Griffiths told BBC Nature: \"We known that farms have to be modern and commercially successful. \"So we look at how to put in wild seed bird plots on less productive areas of the farm - perhaps corners of fields that are difficult to plough - where they can make a big difference to wildlife without having an impact on the productivity of the farm.\" The wildlife charity is working with sustainable farming organisation Conservation Grade and the Pensthorpe Conservation Trust in Norfolk. As part of the project, researchers at Pensthorpe will be carrying out \"taste tests\" with different types of seeds on captive turtle doves. Tim Nevard, executive director of Conservation Grade and a Pensthorpe trustee, said: \"We will trial a number of seed mixtures to identify the most palatable and nutritious options - from breeding to fledging and beyond - so that the right choices about forage habitat creation can be made. \"We will be working closely with Natural England, our nationwide farmer network and commercial partners to encourage widespread uptake of these habitats.\" Other factors that may be contributing to the decline of the turtle dove include illegal hunting in the Mediterranean - as the species makes its annual migration - and the avian disease trichomoniasis, which is common in pigeons and doves. But Ms Griffiths added that a retraction in the birds\' range appeared to be a key cause of the birds\' UK decline. \"We\'ve gained a lot of information [through our research] about where they\'re going, and it really does seem to be about range retraction. \"If don\'t act now, we really could lose them from the UK completely.\"