By: Ruairí Goodwin

Ireland is often described as having a depauperate fauna, particularly when it comes to vertebrates and larger species. Compared to Britain, we have about half the number of bird and mammal species. This relatively poor fauna can be attributed to Ireland’s climatic and geographic history, being separated from mainland Europe far earlier than Britain, which also began to emerge earlier from the ice. It can also be blamed, in part, on human impacts, with many species being extirpated due to persecution and habitat destruction.

In recent decades, Irish society has become increasingly conservation-minded, with growing interest in both protecting existing biodiversity and reintroducing species lost from the island. Despite occasional calls for the reintroduction of wolves, wild boar and resurrected mammoths, more realistic rewilders have often focused their efforts on birds. Since the early 2000s, three bird species have been reintroduced, all large, charismatic birds of prey, none of which are globally under threat and are in fact, are considered ‘species of least concern’. This pattern raises an important question for Irish conservation: why are substantial public resources being devoted to reintroducing widely abundant species, while many native birds currently breeding in Ireland face imminent extinction?

The first species to be reintroduced to Ireland was the golden eagle, when birds were caught in Scotland and released in Donegal’s Glenveagh National Park in 2001. Despite the park being superficially similar to the Scottish Highlands where the species is thriving, the reintroduced population has struggled to sustain itself and has now dwindled to around 25 birds. A recent study attributes this poor establishment to a lack of suitable prey, mountain hares and red grouse in particular, in the landscape due to overgrazing by deer.

Prey abundance has not been an issue for a close relative of the golden eagle, the white-tailed eagle, whose reintroduction began in Killarney National Park in 2007. As this species preys largely on fish, as well as other birds and carrion, they face little challenge in finding food and their population has grown and spread accordingly. The reintroduction programme for this species concluded last year, as a final batch of 26 birds was released, and joined a wild population of over 150 birds found across the island.

A final species, the red kite, was first reintroduced in the same year as the white-tailed eagle, but in Wicklow, in the east of the country. These adaptable raptors have fared well since then, with the Wicklow population expanding into neighbouring counties, being joined by additional reintroduced populations in Fingal and County Down. While encouraging, these successes do not in themselves justify prioritising reintroductions over the conservation of existing, rapidly declining species.

While these reintroductions have taken place over the last thirty years or so, some of Ireland’s most threatened native bird species have experienced precipitous declines. Yellowhammers, formerly common and widespread across the country have declined by around 60%. Curlew have lost 97% of their breeding population and the ring ouzel, an upland species, had only one breeding pair recorded in 2024. The corn bunting is a stark reminder of conservation failings, as this species last bred in Ireland in Mayo in the 1990s and has been considered locally extinct ever since. While all threatened bird species in Ireland are afforded protections, and conservation programmes have reversed the declines of some threatened species, such as the corncrake, resources are spread too thin to effectively conserve all threatened species.

This tension between reintroduction and prevention is further complicated by the fact that several bird species have naturally recolonised Ireland without direct human intervention. Buzzards expanded westward from Britain and are now widespread, while Eurasian cranes bred successfully in Ireland for the first time in centuries without a formal reintroduction programme. Similarly, ospreys, currently the subject of an active reintroduction project, have recently begun breeding naturally. These examples show that natural recolonisation is often possible where suitable habitat exists, raising questions about the necessity and cost-effectiveness of artificial reintroductions.

One justification frequently offered for reintroductions is their potential to deliver wider ecological benefits. All bird species reintroduced to Ireland thus far are large predators and may exert top-down effects on ecosystems. The concept of trophic cascades is well established, the reintroduction of wolves to Yellowstone National Park being a frequently cited dramatic example. While the ecological impacts of reintroduced avian predators in Ireland are likely to be more subtle, their presence may still influence prey populations and ecosystem structure in beneficial ways.

Reintroductions may also act as catalysts for habitat restoration. In Glenveagh National Park, concerns over the survival of golden eagles have led to calls for the restoration of woodland and bog habitats to increase prey density. Implementation of these habitat improvements would benefit many other, such as hen harriers, red grouse and curlews. In this way, reintroduced species simply provide an impetus for ecological restoration and protection, benefitting the wider ecosystem.

The reintroduction of large, charismatic predator species, such as eagles, raises the profile of conservation in Ireland, as well as directly generating revenue. When white-tailed eagles were first brought into the country from Norway in 2007, farmers gathered at the airport to protest their arrival, citing concern for their livestock. The farming community has since become far more receptive of the reintroduced species, with the National Parks and Wildlife Service praising the collaboration of farmers as one of the reasons for the success of the reintroduction. Given the often adversarial relationship between farmers and the conservation movement, this is a step in the right direction, spurred by the reintroduction of white-tailed eagles. Reintroduced species also have the potential to generate significant funds for conservation. A study on the reintroduction of white-tailed eagles to the Isle of Mull in Scotland found that the eagles attracted a minimum of £8 million of tourist spending annually, funds which supported the continued conservation of the eagle and other species.

Nevertheless, these advantages do not negate the need for careful prioritisation. Conservation resources are finite, and investment in one area inevitably reduces capacity elsewhere. In many cases, funding allocated to reintroductions of globally secure species could have a far greater impact if directed toward protecting threatened species and habitats before losses become irreversible.

Future conservation in Ireland should strike a compromise between the benefits of species reintroductions as well as the risks of prioritising these reintroductions over conserving extant species. Reintroduction should only be considered when the species is likely to thrive independently of conservation efforts and where natural recolonisation is unlikely or impossible. Furthermore, the importance and cost of reintroduction programmes should be weighed against the potential to support the conservation of Ireland’s many threatened species. In many cases, funds spent on reintroductions would have a greater effect if instead spent on species conservation in the wild. Reintroductions should be planned with other species in mind, so that protection of reintroduction sites will also benefit other key species and any interest and funds generated from the reintroduction can be used to benefit other species, as well as the wider ecosystem.