The glossy ibis is giving up living on Mediterranean shores for mudflats in Louth and Irish tidal estuaries, such as Lough Atalia in Galway.
The bird’s main breeding ground in southern Europe, Coto Doñana National Park in Spain, has been devastated by drought and water mismanagement, with climate change the chief antagonist.
It may be forced migration but it is a remarkable example of how Ireland’s species mix is changing and creating new ecological dynamics due to global heating – in this case, enriching the biological mix.
The glossy ibis has a distinct throaty croak but its physical appearance, including long curlew-like beak, is most striking. It appears to be dark but up close the iridescent colours in its plumage become evident, especially in sunlight. Their numbers are so large that they are likely to breed here, says Niall Hatch, BirdWatch Ireland’s head of communications and development.
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There is every indication they will follow the pattern of other visitors as they seek foraging areas farther afield. The little egret was once considered rare but, since landing in Youghal in 1997, “very much driven by climate change”, is now breeding here. Hatch predicts the great white egret, cattle egret and Mediterranean gull will follow a similar pattern.
This is due to changed climatic conditions in Ireland but also more dramatic changes in intervening areas, notably milder winters in much of mainland Europe, where in the past cold conditions forced birds to “retreat or die”.
Sightings of the African hoopoe this spring caused a stir among birders but Hatch says this was probably due to “overshooting its breeding grounds and staying for a few days”.
[ Hoopoes ‘overshoot’ France and land in Ireland and BritainOpens in new window ]
Just as a heating world brings exotic species to our doorstep, he says it is also accelerating loss of Ireland’s farmland bird populations and the demise of the Arctic tern, common scoter, red throated diver and ring ouzel – because of changes to food sources and breeding habitats.
Zoologist Collie Ennis keeps an eagle eye on new visitors that are obvious threats or may become established and then become threats, with climate change a contributory factor in most cases. Many invertebrates – spiders, worms, snails, lobsters, crabs and insects – “did not get a foothold in the past and can get a foothold now”, as the recent arrival of the Asian hornet has shown.
Other island countries have taken biosecurity seriously but not Ireland, he says. Invasive species – pests, creatures and plants – are happy to avail of ecosystems increasingly being undermined by climate change.
Up to now, “we have been lucky because of our [relatively] cold climate. We have to become more observant as a nation and government policy has to tighten things up.”
He welcomes increased native forests, yet oak is imported from mainland Europe, bringing the threat of the oak processionary moth. “We should be growing our own saplings,” says Ennis, who is based in Trinity College Dublin.
He worries about the beautiful but deadly alpine newt already in the midlands. It transmits the devastating chytrid fungus and other diseases to native amphibians. The spruce bark beetle has killed hundreds of millions of trees across Europe, has made it as far as England and could be here next.
Responsiveness has improved, he says, through the National Biodiversity Data Centre (NBDC) reporting portal invasive.ie as demonstrated in tracking the Asian hornet with the public’s help.
The centre is enhancing tools to identify troublesome species that are here and ones that may be on the way, factoring in whether they benefit from climate change, says its invasive species programme manager, John Kelly.
Its focus is what might be introduced by humans in, for instance, imported products or in ship fouling, that may have a negative economic or biodiversity impact – rather than natural dispersal from the Continent.
There is much attention is on “environmental suitability”. The Asian hornet has moved from “low suitability” in Ireland in the 1990s. When he became aware of it in 2006, Kelly saw its foothold in the Mediterranean and said to himself, “We don’t have the same climate, so we don’t have to worry about it”.
In 2025, it is a risk to Ireland under current and future climate conditions, so the centre is beginning to model what might be coming down the tracks. Countries with an annual mean temperature of about 10-15 degrees have the highest suitability; Met Éireann data shows Ireland’s current average is about 10 degrees and rising.
The HSE continues to monitor ports and airports for the arrival of the Asian tiger mosquito and Egyptian mosquito, which carry malaria, yellow fever and dengue fever. So far Irish mosquitoes have been shown not to carry malaria, while conditions are too cold to sustain large numbers needed for infection to spread.
The tiger mosquito, however, needs a temperature of about 20-25 degrees to survive, and if Irish winters continue to get milder, it could become a permanent resident.
In addition, there are more midges in Ireland – many of the biting variety – due to climate change, as warmer temperatures, increased humidity and fewer frosts create more favourable conditions for breeding and survival.
University of Galway researchers say the rise in venomous black widow spiders is probably due to global heating, as it allows them to thrive in areas once too cold for it to live in.
There have been many changes too in the Irish marine species mix but the extent to which this is attributable to climate change is another matter, says fisheries scientist Graham Johnston of the Marine Institute.
Its annual pelagic survey shows clear trends. Among small fish, anchovies and sardines are much more prevalent, while among larger species, the rebound in numbers of Atlantic bluefin tuna stands out.
This is not simply a case of fish moving north due to warmer waters, he says, but is interlinked with changes in plankton and current movements.
A newcomer to Irish shores in summertime is the fearsome looking grey triggerfish. They have small mouths but eight sharp teeth and strong jaws, useful for crushing the shells of mussels and other prey.
With sea surface temperature in Irish waters increasing at an unprecedented rate of about 0.6 degrees per decade since 1994, it has attracted this and other newcomers more familiar to fishermen around the Mediterranean.
Unlike the octopus, which is confined to the southern Irish waters, the triggerfish is moving north. While they haven’t bred here yet, scientists expect they will become more established as seas continues to warm.
Increased sightings of dolphins, humpback whales and basking sharks are linked to a combination of climate change, shifts in prey distribution and the ending of historical whaling operations.
Jellyfish, both number and variety, are cropping up on Irish coasts and beaches in greater numbers. This is partly attributed to climate change, overfishing causing predators to keep the number of jellyfish at manageable levels, and enrichment of water by algae, which reduce jellyfish predators and provide more food for them.
The arrival of new species can provoke surprising responses, says TCD zoologist Prof Yvonne Buckley. She cites the welcome increased presence of the great spotted woodpecker in Ireland, yet it has led to a social media frenzy and misinformation that the bird is weakening and killing trees. This may have stemmed from damage to some wooden electricity poles caused by the bird – a problem that emerged after recent storms.
“People are jumping to conclusions when they see something new,” she says. The woodpecker is “moving in naturally to Ireland due to climate change but also because there are more trees in Ireland now. Something new is not necessarily bad.”
