A trial scheme using 'foster parents' to raise young turtle doves has succeeded in boosting the captive population of the threatened species – but the veteran conservationist who came up with the idea is baffled as to why these precious birds have not been released into the wild.
The alarming decline of the turtle dove in the last 50 years has united conservationists in their efforts to save this species from the brink of extinction.
Once widespread, the population has plunged by more than 90pc since the 1970s, attributed to factors ranging from the effect of modern farming on traditional feeding grounds, to the threat from hunting along the migration route to Africa.
But while nature-lovers and wildlife charities are agreed about the urgency of the problem, there are differing opinions on the best way to secure the bird's future.
One debate surrounds a collection of about 30 birds at Pensthorpe Natural Park near Fakenham – the product of an innovative trial using avian 'foster parents' to bolster the captive population.
Once the eggs were laid in the spring, they were removed from the turtle doves and placed under barbary doves, who successfully raised the chicks as their own, while another batch was laid by the turtle doves.
The scheme was the idea of Bill Makins, who founded Pensthorpe in the 1980s, but is no longer formally connected with the reserve after selling it to its current owners, Bill and Debs Jordan, in 2003.
He said the situation facing the turtle dove was now so dire that the birds should have been released in the autumn, as they would have no effect on the natural population, and could be monitored to give valuable knowledge about their breeding, feeding and migration.
But this approach has not been taken by Operation Turtle Dove, launched in 2012 to reverse the population decline, whose partners include the Pensthorpe Conservation Trust and the RSPB. They said there were ethical questions about releasing captive-bred birds, from a limited gene pool, into a wild environment where the root causes of the population crash have not yet been corrected.
Mr Makins, 84, said: 'Turtle doves in captivity are prolific breeders and will lay a lot of eggs, so this system could be ramped up quite easily and is well understood by those who breed both canaries and fancy pigeons. The young birds were moved to much bigger aviaries where they retain their 'wildness' and should have been released into the wild in autumn.
'Using this method of boosting the local turtle doves will not affect the wild birds at all, as it is coming from a population which does not exist. A great deal will certainly be learned, and if the birds are shot on the way to Africa, as many thousands from Europe are every year, it will not affect the British population.
'It is not illegal to release these birds. If they had been released they could be colour-rung, there would be no confusion, they could be monitored and we would learn quite a lot from them.
'Are they waiting for the turtle dove to die out before they do it? It is much better to do it now while there is still a wild population.
'They say we must get the habitat right first. The RSPB is trying to put farming back 50 years, but you cannot turn back the clock. You have to work with farming – and it can be done.'
One supporter of Mr Makins' approach is his friend, wildlife photographer and retired farmer Chris Knights, who used to run a 9,500-acre arable farm at Gooderstone, near Swaffham. He agreed that more needed to be done to create the right farmland habitats.
'Turtle doves like sparse vegetation with 25-30pc of ground cover, with the rest being bare ground,' he said. 'It is really what a farmer would call a crop failure.
'Since the 1990s farming has been stepping up and stepping up and if a farmer was not very efficient, he would go out of business. It is so clean now, there are no weeds, and no grain spilled for the birds to eat.
'The farmers are not to blame. They are fighting for survival, just the same as the turtle doves.'
Chrissie Kelley, head of species management at Pensthorpe Natural Park, said there were many issues to consider and much more research to be carried out before the Operation Turtle Dove partners would consider a reinforcement of captive-bred birds into the wild.
'None of us want to see the turtle dove go extinct, but we need to be confident that we are doing the right thing,' she said.
'There is much going on with turtle doves behind the scenes here at Pensthorpe, through its partnership in Operation Turtle Dove; we are helping with trials for satellite tracking, as well as feeding and crop trials on the farm. Creating the right habitat and feeding for the birds is essential. Are we able to counteract the factors that have had such a detrimental effect on the population?
'Any release programme should follow correct protocols, and that takes time. The IUCN (International Union for Conservation of Nature) guidelines are there to make people think through a project they have got in mind, and the feasibility of doing it. It needs serious consideration and a multidisciplinary approach, as well a thorough system of monitoring to see if the release is successful.
'We also need to consider the impact on the wild population, our birds have been bred in captivity for many years, there could be issues with genetically compromised individuals. Breeding for aviculture is very different to breeding for release, and we would need to be confident that any birds released into the wild would stand the best possible chance of survival.
'This trial with the fostering has been very interesting and has shown it is feasible to use this method to rear a good number of birds. I would like to consider that we could use our experience from this trial and look to a project to create an 'ark population' from birds that are still in the eastern counties, before they disappear, ensuring an 'insurance policy' for turtle doves in the UK.'
RSPB response
After turtle doves were successfully surrogate-reared in captivity in Norfolk, the RSPB explained why these captive-bred birds could not be released into the wild to help boost the UK's dwindling population.
Rupert Masefield, the RSPB's lead communications officer for Operation Turtle Dove in East Anglia, said: 'There are lots of reasons why the RSPB and Operation Turtle Dove does not support releasing captive-bred turtle doves into the British countryside as a means of boosting the wild population, but the fundamental one from a conservation perspective is that it would not help turn around the fortunes of the turtle dove.
'The mission of Operation Turtle Dove is to reverse the decline of the European turtle dove in the UK and Europe by identifying and addressing the underlying causes. The main factor affecting turtle dove breeding success here in the UK is thought to be the disappearance of the turtle dove's food plants from the British countryside and farmland. Turtle doves that come to the UK in the summer to breed eat the seeds of arable weeds, which have become increasingly scarce as a result of ever-intensifying farming practices. Releasing captive-bred birds into the countryside would do nothing to improve this situation. In fact, the captive-bred birds might well end up competing for the limited food resources with wild birds.
'As the only migratory dove in Europe, turtle doves also face a wide range of varied threats outside the UK, which range from issues of food availability on their migratory flyway and in their wintering grounds, loss of nesting habitat, disease, climate change impacts, and unsustainable levels of hunting. Addressing these underlying pressures which are all contributing to turtle dove's decline first and foremost should be the focus of conservation efforts here in the UK and elsewhere in Europe and Africa.'
What is being done on farms?
UK conservationists have focused much of their effort on increasing feeding habitats for turtle doves, studying their habits and then designing different seed mixes and management techniques which farmers can implement as part of their Countryside Stewardship options.
But Mr Makins said the current advice given to farmers needed to be improved. He said turtle doves needed scrubby areas with sparse vegetation and patches of bare ground to walk on in search of grain and seeds, which can be sown as a supplementary food source in summer.
'But all the bird strips we have seen have been useless because they are too high and have not got the right plants in them,' he said.
'I think farmers are always going to find it difficult to create the sort of conditions which turtle doves need, but it can be done to some extent.'
Nicola Williamson, the RSPB's senior farmland conservation officer, said: 'RSPB farm conservation advisers work closely with many farmers to help them make the best use of Countryside Stewardship options targeted at helping particular species and to manage areas of wildlife habitat on their farms in the best way for the wildlife they are designed to help.
'As part of Operation Turtle Dove, the RSPB has been working with farmers and conservation scientists to test how well different options for creating and managing turtle dove foraging habitat work for turtle doves when they are implanted on the ground on farms in the UK countryside. One such recent study completed in 2015 found that 'scarifying' (scraping) and 'topping' of autumn-sown seed mix tailored for turtle doves the September after sowing helps to create areas of bare ground to allow turtle doves to more easily access the seed in the second year after the creation of the feeding habitat.'
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here