Butterflies die by the million in freezing Mexican forest

PHIL DAVISON

Latin America Correspondent

Between 20 and 30 million of the world's most beautiful butterflies, of the North American Monarch species, may have been wiped out by snow and freezing weather this week in the Mexican mountain forest where they spend the winter.

Mexican ecologists who visited the Oyamel fir forest in the state of Michoacan reported that at least a third, possibly half, of the estimated 60 million hibernating Monarchs had frozen to death or been buried under a foot of snow.

The picturesque orange-and-black butterflies are renowned for their 3,000- mile odyssey from the northern United States and Canada to the same Mexican forest every winter, taking up to three months at 30 miles a day and an altitude of one mile.

"The situation is devastating," said Homero Aridjis, a Mexican poet and leader of the "Group of 100" lobby of environmentalists. "Two of our biologists visited the butterflies' winter reserves and estimated that at least one- third had been wiped out, blown from their perches on the fir trees and buried in the snow. It's possible up to half of them have died."

Despite the catastrophe, the Monarchs, known to science as Danaus plexippus, are not endangered as a species by their latest losses. They are more threatened by increased logging of their reserves, which is removing their protection from the elements, Mr Aridjis said. They will probably restore their numbers quickly if breeding conditions are good on their way back to the north, he added.

An unusually bad snowstorm which occurred in 1992 wiped out at least 70 per cent of the hibernating Monarchs in Michoacan state, but the butterflies are already close to their previous levels.

After flying down in October from as far north as Ontario, the Monarchs settle beneath the normal snow line over several square miles of forest west of Mexico City on mountains that reach more than 10,000ft.

Visitors who trek to see them in normal weather are stunned by a solid landscape of orange and black as the butterflies cover the ground and trees. If disturbed, they almost black out the sky and sound like a heavy drizzle as they flutter in their millions.

It is impossible to visit the area without trampling hundreds, if not thousands of Monarchs underfoot, since they also cover all pathways, a dilemma which has led Mr Aridjis's group to call on the Mexican government to restrict access to the reserves.

Picnickers who play loud music and leave litter also endanger the butterflies, but their biggest problem of recent years has been the gradual deforestation of the area by loggers.

The local Oyamel fir trees usually act as an umbrella for the butterflies against heavy rains and rarer snow storms, such as the one last weekend.

On their flight from the north-eastern US and Canada the butterflies stick to the US east coast and invariably make a "pit stop" around St Marks in Florida to gorge themselves on milkweed, which will give them enough body fat to survive the winter.

While milkweed's poisonous sap is avoided by most other creatures, it is absorbed by the Monarchs and gives them a natural defence against predators.

Monarchs often live up to 10 months, mostly surviving the epic journey south but dying while laying their eggs along the Gulf coast of the US - in Louisiana, Mississippi, Alabama or Florida - on their more westerly return trip.

Start your day with The Independent, sign up for daily news emails
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

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...

Recruitment Genius: Customer Service Advisor

£16575 - £19000 per annum: Recruitment Genius: An excellent opportunity is ava...

Day In a Page

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
Paris Fashion Week

Paris Fashion Week

Thom Browne's scarecrows offer a rare beacon in commercial offerings
A year of the caliphate:

Isis, a year of the caliphate

Who can defeat the so-called 'Islamic State' – and how?
Marks and Spencer: Can a new team of designers put the spark back into the high-street brand?

Marks and Spencer

Can a new team of designers put the spark back into the high-street brand?
'We haven't invaded France': Italy's Prime Minister 'reclaims' Europe's highest peak

'We haven't invaded France'

Italy's Prime Minister 'reclaims' Europe's highest peak
Isis in Kobani: Why we ignore the worst of the massacres

Why do we ignore the worst of the massacres?

The West’s determination not to offend its Sunni allies helps Isis and puts us all at risk, says Patrick Cockburn
7/7 bombings 10 years on: Four emergency workers who saved lives recall the shocking day that 52 people were killed

Remembering 7/7 ten years on

Four emergency workers recall their memories of that day – and reveal how it's affected them ever since
Humans: Are the scientists developing robots in danger of replicating the hit Channel 4 drama?

They’re here to help

We want robots to do our drudge work, and to look enough like us for comfort. But are the scientists developing artificial intelligence in danger of replicating the TV drama Humans?
Time to lay these myths about the Deep South to rest

Time to lay these myths about the Deep South to rest

'Heritage' is a loaded word in the Dixie, but the Charleston killings show how dangerous it is to cling to a deadly past, says Rupert Cornwell
What exactly does 'one' mean? Court of Appeal passes judgement on thorny mathematical issue

What exactly does 'one' mean?

Court of Appeal passes judgement on thorny mathematical issue