Ask Onix
Aspen's remarkable journey across Ireland
A white-tailed eagle named Aspen has traversed 26 counties on the island of Ireland in just 48 days, completing an unprecedented aerial circuit that captivated ecologists and the public alike.
From Cork to the coasts: A 48-day odyssey
Hatched last year in Glengarriff Nature Reserve, County Cork, Aspen embarked on her journey on 22 March. Satellite tracking revealed a route spanning Leinster, Ulster, and Connacht before she returned to her native Munster. Her travels included stops in five Northern Ireland counties: Armagh, Down, Tyrone, Londonderry, and Fermanagh.
White-tailed eagles, known for their 2.5-metre wingspan, were hunted to extinction in Ireland and the UK by the early 20th century. Reintroduction efforts, primarily using eagles from Norway, have since restored populations in several regions, including Kerry, Cork, Clare, Galway, and Donegal.
A bird with a personality
Clare Heardman, an ecologist with the National Parks and Wildlife Service (NPWS), has monitored around 90 eagles as part of the reintroduction programme. She described Aspen as a bird with a wanderlust streak, noting that her first solo flight involved a sweeping loop of Munster.
"I helped tag her when she was eight weeks old, then she fledged at 13 weeks. Since then, she's shown she definitely isn't a home bird. Travelling is in her personality."
Clare Heardman, NPWS ecologist
Aspen's name, inspired by an unusual tree near her nest, has endeared her to the public. Heardman admitted a special bond with the bird, citing her named status, her neat circuit of Ireland, and her lineage-offspring of a local pair she watched grow from chicks.
Why the journey resonated
Dr Eimear Rooney of the Northern Ireland Raptor Study Group (NIRSG) explained that young eagles often roam during spring, riding thermal currents to cover vast distances quickly. Aspen's route, which hugged coastlines and wetlands, aligns with the species' preference for fish and marine life, though they also scavenge for carrion inland.
"This time of year, it's common for white-tailed eagles to go wandering. They get on a hot air current and, because of their size, can cover miles in a short time."
Dr Eimear Rooney, NIRSG
Rooney speculated that Aspen's detours into Donegal's hills were likely driven by scavenging opportunities, as the birds survey high ground for food.
The perils of adolescence
White-tailed eagles typically begin breeding at four or five years old, but adolescence is fraught with danger. Threats include poisoning-two eagles were confirmed poisoned in County Antrim in May 2023-wind turbine collisions, storms, and avian flu.
Rooney emphasised the uncertainty of their paths: "They're just trying to find their way-food, security, and other eagles. What they really want is somewhere to settle and breed. Just because Aspen was released in Cork doesn't mean she'll stay there."
Common migration routes often lead eagles to Scotland via the Antrim Hills and Rathlin Island, but their destinations remain unpredictable.
A symbol of conservation success
In 2024, a pair of white-tailed eagles bred in County Fermanagh, marking the first such event in Northern Ireland in over 150 years. The species' resurgence, coupled with Aspen's high-profile journey, has bolstered public engagement with conservation efforts.
Heardman attributed the public's fascination to Aspen's route, which touched nearly every corner of the island. "It's helped people relate to her," she said, noting the bird's newfound popularity on social media.
