The conservation and recovery of threatened species is rewarding, demanding and always complex. What might work for one can be a less successful approach for another. The particular circumstances and characteristics of a species must always be carefully considered when determining any approach, to ensure that it will have a positive impact on the population.
Conservation should always be carried out in an effective, sustainable and ethical way. Operation Turtle Dove and its founding partners, the RSPB, Natural England, Pensthorpe Conservation Trust and Fair to Nature, have taken an evidence-based approach to understand what the limiting factors for Turtle Doves are, tested solutions, and continue to consider how these should be best implemented.
Operation Turtle Dove is aware of reports of individuals and groups releasing captive-bred Turtle Doves. Whilst well intentioned, we do not currently support the release of captive-bred Turtle Doves as a conservation measure.
Supplementing the population with birds raised in captivity provides an instant increase in numbers and feels like a positive and immediate action. However, for Turtle Doves in the UK, it also brings risks that may be detrimental to the existing population, does not address the underlying reasons for the decline, and, we believe, is not currently needed. The reasons for this are:
- The release of captive-bred Turtle Doves does not currently meet the internationally recognised IUCN guidelines or Defra code for species reintroductions or other conservation translocations. It is also not supported by the International Species Action Plan for the European Turtle Dove.
- In the UK, evidence shows that the availability of seed food during the breeding season has been the principal limiting factor and this alone explained the decline in the breeding population up to the end of the 20th century. The UK’s highest priority conservation action for Turtle Doves is the delivery of more high-quality breeding habitat, including sufficient foraging areas.
- Currently, Turtle Doves numbers in the UK do not need to be artificially increased. The UK breeding population is part of a now recovering western European population of some two million breeding pairs. Being long-distance migrants, Turtle Doves are capable of naturally repopulating areas of the UK provided suitable habitat is available.
- The risks associated with releasing captive-bred birds to the wild population include disease transmission and genetic contamination, potentially resulting in changes to migratory behaviour. These are real risks that could have a negative impact on the existing wild population.
- Any attempts to establish a resident, non-migratory population of Turtle Doves in the UK carry an unwarranted level of risk, as all wild Turtle Doves breeding in Europe are long-distance migrants not adapted to European winter conditions.
Operation Turtle Dove and its partners remain committed to working with farmers, landowners and other partners to support the creation of more widespread suitable habitat for Turtle Doves in the UK. This includes through our team of Turtle Dove conservation advisors who provide bespoke advice on how to create the feeding, nesting and drinking habitats that the birds need. Together, we can continue reversing the decline of one of England’s best-loved farmland birds.
Conservation guided by science
Two key documents provide guidelines on whether conservation translocations, including through the release of captive-bred birds, is appropriate for any particular species in England: the IUCN’s Guidelines for Reintroductions and Other Conservation Translocations and Defra’s Reintroductions and other conservation translocations: code and guidance for England.
Both lay out the process that should be followed when considering a species reintroduction, or other type of conservation translocation. This includes feasibility assessments, identification of objectives, implementation of a monitoring strategy, and dissemination of results. Applying these to the Turtle Dove allows assessment of its appropriateness for the recovery of the species.
Have the factors that caused the original decline of Turtle Doves in the UK been addressed?
There is good scientific evidence that the Turtle Dove population decline in the UK and across north-west Europe since the 1970s has been driven by two factors. Up to the 1990s, their decline could be explained by the loss of seed food in the breeding season due to changes in agricultural practices, and the associated reduction in the numbers of chicks fledged annually by each breeding pair of Turtle Doves. This was subsequently compounded by unsustainable levels of hunting along the birds’ migratory flyway in south-western Europe; in countries through which all western European breeding Turtle Doves migrate. In the years prior to 2019, up to one million Turtle Doves were being hunted each year in total across France, Spain and Portugal.
Significant progress has now been made in addressing the legal hunting of Turtle Doves. In 2018, the RSPB led on an international conservation action plan working with experts from across the Turtle Dove’s range. Together they identified the main problems Turtle Doves faced and crucially the most effective solutions which would help numbers increase. Successful campaigning led to an evidence-based hunting management system (‘Adaptive Harvest Management’) that was put in place by the European Commission from 2021 onwards. The first phase of this system was a complete moratorium on hunting in western Europe from 2021 to 2024. Over the same period, there has been a rapid and encouraging start to population recovery; an increase of over 30% in the western European breeding population as a whole, in just three years. As expected, much of this initial increase has been recorded in the core of this breeding population in Spain where historic breeding densities were highest.
As a result of this rapid start to population recovery, the second phase of the Adaptive Harvest Management process will be to permit a much more limited level of hunting. This will be reviewed annually and set at levels to allow continued growth and recovery of the western European breeding population. In the event that population recovery stalls or reverses, the system is designed to respond by further reducing the amount of hunting permitted (including back to zero if required). Similar Adaptive Harvest Management systems have been used successfully to sustainably conserve wildlife populations elsewhere in the world where hunting is permitted.
The availability of foraging and nesting habitat in the UK has increased through the work of conservation organisations and programmes such as Operation Turtle Dove working in partnership with farmers and other land managers. There is an increasing number of case studies demonstrating that this approach leads to more Turtle Doves being recorded.
But there is still much to be done. Current availability of good quality breeding season habitat (nesting and foraging) in the UK remains significantly below the levels present on farmland in the ‘70s. It is the single most significant limiting factor to the species’ recovery in the UK. Evidence from sites such as the Knepp Estate shows that when good quality habitat is provided, numbers of Turtle Doves can increase without requiring further measures.
Until the shortage of habitat in the UK is fully addressed, there is no merit in releasing captive-bred birds.
Has the UK breeding population of Turtle Doves reached a size and status that requires reintroduction?
The number of birds breeding in the UK remains relatively small (estimated at 2,096 territories in 2021). However, it should be seen in the context of being part of the much larger and highly mobile western European population that totals approximately two million territories. Being long-distance migrants, Turtle Doves can travel 600km in one night and are very capable of naturally recolonising appropriate habitats, provided they are available. With a sustainable hunting management system now in place and the core of the population growing on the continent, the focus needs to be on continuing to increase the amount of suitable habitat in the UK capable of supporting the increasing numbers that are anticipated to reach here in the coming years.
Does releasing captive-bred Turtle Doves risk introducing and spreading disease?
Pigeons and doves are susceptible to a range of diseases including Trichomoniasis and Highly Pathogenic Avian Influenza (HPAI). In captivity, birds are raised in close proximity to each other, increasing the risk of disease transmission. Unless very high levels of biosecurity are used, releasing birds from captive-bred stock is likely to increase the risk of transmission in the wild population. With no existing control or licensing for the rearing of Turtle Doves, the risk of poor biosecurity represents a risk to the existing wild population.
Could the release of captive-bred Turtle Doves adversely affect natural behaviour?
Turtle Doves have evolved to be an obligate long-distance migratory species, spending the winter in sub-Saharan Africa. However, birds across Europe reach their destination via different ‘flyways’. Those that breed in the UK, and all others breeding in Western Europe all follow the ‘western flyway’, travelling south-west through France, the Iberian Peninsula, Morocco and down the west coast of Africa. Birds breeding further east follow the central and eastern flyways along routes south, or south-eastwards through Italy, or the Balkans. Furthermore, birds are likely to have adapted to regional conditions and may not be physiologically suited to other areas.
The introduction of birds from either inappropriate or unknown provenance has the potential to genetically contaminate the wild population. This is recognised by the International Species Action Plan for Turtle Dove as a serious risk to the species. With no existing licensing system or monitoring to ensure this doesn’t happen, this presents a threat to their recovery.
Additionally, establishing a resident, non-migratory population of Turtle Doves through a process known as ‘hefting’, has previously been advocated by some. The viability of this is debatable but is a highly unnecessary attempt to change the birds’ natural behaviour. It carries multiple risks including increased disease transmission due to weakened condition and greater contact with wintering flocks of other species at feeding sites, as well as the welfare of the released birds that are physiologically unsuited to winter conditions in the UK.