Killer mice are driving island's rare birds to extinction

A A A

More than a million albatross, shearwater and petrel chicks, some goose-sized and weighing more than 20lbs, are being eaten alive every year - by mice.

The mice are descendants of the British house mouse, probably taken to Gough Island, south of Tristan da Cunha, by ships in the 19th century - but have grown to double the size of their ancestors. They have also become carnivores and learnt to attack big seabird chicks which, having evolved over millions of years on an island with no natural predators, do not know how to defend themselves.

The mice attack at night, singly or in groups, gnawing into the chicks' bodies when they sit on the nest, and eventually kill them through blood loss or destruction of vital organs.

The scale of the killing has astonished ornithologists who discovered it. It is thought it might eventually drive some of the 22 species of birds that breed on Gough to extinction.

Now the Royal Society for the Protection of Birds (RSPB) has been awarded a grant of more than £60,000 by the UK government's Overseas Territories Environment Programme to fund additional research on the Gough Island mice and a study of how to deal with them.

The slaughter was discovered by Richard Cuthbert, a research biologist for the Royal Society for the Protection of Birds (RSPB), and his colleague, Erica Sommer, from Cape Town University when they spent a year working on Gough in 2000-2001. It has been confirmed by video footage of the attacks taken by Ross Wanless, a PhD student from the University of Cape Town's Percy FitzPatrick Institute, and his colleague Andrea Angel.

"The albatross chicks spend eight months sitting waiting for food from their parents," Dr Cuthbert said. "They are nearly a metre tall and 250 times the weight of the mice, but are largely immobile and cannot defend themselves. For a carnivorous mouse population on one of the wettest and windiest places on earth, it is an easy meal of almost unimaginable quality. The result is carnage."

Gough, a UK Overseas Territory and a dependency of St Helena, is one of the most remote and hostile environments in the world, a mountainous island without permanent human inhabitants, in the Roaring Forties - an area of extreme winds.

But it is also a World Heritage Site hosting more than 10 million seabirds, including 99 per cent of the world's Tristan albatross and Atlantic petrel populations - the birds most often attacked. Just 2,000 Tristan albatross pairs remain.

"Gough Island hosts an astonishing community of seabirds and this catastrophe could make many extinct within decades," said Geoff Hilton, another RSPB research biologist. "We think there are about 700,000 mice, which have somehow learnt to eat chicks alive - much like blue tits learnt to peck milk bottle tops. The albatross chicks weigh up to 10kg and, ironically, albatrosses evolved to nest on Gough because it had no mammal predators - that is why they are so vulnerable. The mice weigh just 35 grams; it is like a tabby cat attacking a hippopotamus."

Mr Wanless said: "There are mice on other South Atlantic islands but Gough is the only site where this is known to be happening. Once one mouse has attacked a chick, the blood seems to attract others. They gnaw into the chick's body, create a gaping wound and the chick weakens then dies over several days."

Scientists suspect that the mice are also eating the eggs and chicks of the rare, ground-nesting Gough bunting, a small finch found nowhere else in the world. Researchers think the finch has been forced from the best nesting sites into less suitable upland areas. "This species is one of the most worrying because there is no other population in the world," Dr Hilton said.

The mice on Gough could be killing far more than one million chicks each year, the researchers estimate. About 1,000 Tristan albatross chicks are killed annually by mice and in 2000 and 2001, 60 per cent - 700,000 - of Atlantic petrel chicks died before fledging, probably because of mice. Many of the chicks of the one million great shearwaters are also killed by mice. .

The Gough mouse, typically weighing between 27g and 40g compared to 15g for a house mouse in the UK, is one of 2,900 non-native species damaging native wildlife on the 17 UK Overseas Territories and Crown Dependencies a review by the Joint Nature Conservation Committee (JNCC) has found.

Vin Fleming, head of the international unit at the JNCC said: "Non-native species are a major cause of the loss of biodiversity globally and their impacts are especially severe on island ecosystems typical of our Overseas Territories."

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: SAGE Bookkeeper & PA to Directors

£18000 - £24000 per annum: Recruitment Genius: An exciting opportunity has ari...

Recruitment Genius: Online Sales and Customer Services Executive

£15000 - £18000 per annum: Recruitment Genius: An On-line Sales & Customer Ser...

Recruitment Genius: Accounts Assistant - Fixed Term Contract - 6 Months

£15000 per annum: Recruitment Genius: One of the largest hospitality companies...

Recruitment Genius: Electricians - Fixed Wire Testing

£28000 - £32000 per annum: Recruitment Genius: As a result of significant cont...

Day In a Page

Seifeddine Rezgui: What motivated a shy student to kill 38 holidaymakers in Tunisia?

Making of a killer

What motivated a shy student to kill 38 holidaymakers in Tunisia?
UK Heatwave: Temperatures on the tube are going to exceed the legal limit for transporting cattle

Just when you thought your commute couldn't get any worse...

Heatwave will see temperatures on the Tube exceed legal limit for transporting cattle
Exclusive - The Real Stories of Migrant Britain: Swapping Bucharest for London

The Real Stories of Migrant Britain

Meet the man who swapped Romania for the UK in a bid to provide for his family, only to discover that the home he left behind wasn't quite what it seemed
Katy Perry prevented from buying California convent for $14.5m after nuns sell to local businesswoman instead

No grace of God for Katy Perry as sisters act to stop her buying convent

Archdiocese sues nuns who turned down star’s $14.5m because they don’t approve of her
Ajmer: The ancient Indian metropolis chosen to be a 'smart city' where residents would just be happy to have power and running water

Residents just want water and power in a city chosen to be a ‘smart’ metropolis

The Indian Government has launched an ambitious plan to transform 100 of its crumbling cities
Michael Fassbender in 'Macbeth': The Scottish play on film, from Welles to Cheggers

Something wicked?

Films of Macbeth don’t always end well - just ask Orson Welles... and Keith Chegwin
10 best sun creams for body

10 best sun creams for body

Make sure you’re protected from head to toe in the heatwave
Wimbledon 2015: Nick Bollettieri - Milos Raonic has ability to get to the top but he must learn to handle pressure in big games

Nick Bollettieri's Wimbledon files

Milos Raonic has ability to get to the top but he must learn to handle pressure in big games
Women's World Cup 2015: How England's semi-final success could do wonders for both sexes

There is more than a shiny trophy to be won by England’s World Cup women

The success of the decidedly non-famous females wearing the Three Lions could do wonders for a ‘man’s game’ riddled with cynicism and greed
How to stop an asteroid hitting Earth: Would people co-operate to face down a global peril?

How to stop an asteroid hitting Earth

Would people cooperate to face a global peril?
Just one day to find €1.6bn: Greece edges nearer euro exit

One day to find €1.6bn

Greece is edging inexorably towards an exit from the euro
New 'Iron Man' augmented reality technology could help surgeons and firefighters, say scientists

'Iron Man' augmented reality technology could become reality

Holographic projections would provide extra information on objects in a person's visual field in real time
Sugary drinks 'are killing 184,000 adults around the world every year'

Sugary drinks are killing 184,000 adults around the world every year

The drinks that should be eliminated from people's diets
Pride of Place: Historians map out untold LGBT histories of locations throughout UK

Historians map out untold LGBT histories

Public are being asked to help improve the map
Lionel, Patti, Burt and The Who rock Glasto

Lionel, Patti, Burt and The Who rock Glasto

This was the year of 24-carat Golden Oldies