It is a delicate process but for Gayle Hall it is a labor of love: tagging monarch butterflies as part of a program to monitor the movements of one of nature's most celebrated migrants.
GRAPEVINE, Texas -- It is a delicate process but for Gayle Hall it is a labor of love: tagging monarch butterflies as part of a program to monitor the movements of one of nature's most celebrated migrants.
"I've tagged 580 monarchs for release today." she said as she held one of the insects gently in her hand, the tiny tag a clear white circle standing out from the intricate orange, black and white of its wing.
Hall's butterflies were released at an annual festival in the Texas city of Grapevine that honors the monarchs, famed for their overland migrations from Canada to Mexico and back again. Hall is Grapevine's director of events and has tagged many a monarch over the years.
Some monarchs travel up to 3,000 miles in a journey which is unique in the butterfly world.
Grapevine, a heavily-forested city just north of Dallas, lies on the monarch migration route and insects released at previous festivals have been found in Mexico.
Each tag -- which is pressed onto the insect's wing -- has a unique identification number and a toll-free telephone number and e-mail address to contact if a person happens to catch the butterfly or finds one dead.
The information is helping scientists to gather a database on the monarchs, which face a range of threats.
MONITORING MONARCHS
"It varies, but in good years we tag somewhere between 80,000 and 100,000 monarchs," said Chip Taylor, an insect ecologist at the University of Kansas who heads up Monarch Watch (http://www.monarchwatch.org), the monitoring program behind the tags.
Most of the monarchs are caught in the wild for tagging though some, such as the insects released at the Grapevine festival, are farmed by breeders.
Even the reared ones instinctively join the migration, which is currently taking places with hundreds of millions of butterflies heading south to their Mexican wintering grounds.
Taylor said the program enabled scientists to gather data while raising public awareness -- twin goals crucial to monarch conservation.
"Usually people who find these things have never heard of our program and are quite astonished when they find a tag," Taylor told Reuters in a telephone interview.
The program has been in place since 1992 and Taylor said the one certainty to emerge from the 14-year database was that monarch populations varied widely from year to year, mostly it seemed from weather-related factors.
The populations which winter at several sites west of Mexico City are the benchmark for monarch numbers and they are counted by the hectares they cover. Each hectare (2.47 acres) is estimated to hold between 25 to 75 million monarchs.
The biggest recorded wintering population in the past 14 years was in 1996-1997, when 21 hectares were cloaked in a blaze of orange and black.
This year Taylor expects the butterflies to cover around 6.5 hectares -- well below the average of nine hectares, mostly because of dry conditions this summer over much of the insect's range.
"If you are going to conserve an organism you really have to understand the dynamics of the population and get a handle on the numbers," Taylor said.
This is very much a long-term project -- Taylor said 14 years was not enough time to tell if the population was in decline or not, though other factors suggested it probably was.
"The long-term outlook for the monarchs is not good," he said, pointing to illegal logging in Mexico and urban development in the United States -- two forces that were eating away at its habitat. Climate change linked to greenhouse gas emissions could well be another threat.
The insects already have plenty of natural hazards en route including predatory birds.
The autumn migration is the highlight of the cycle. The spring and summer migrations span generations in a gradual recolonization of the northern territory before the last batch makes the long trek back to Mexico.
At the Grapevine festival, delighted children released the insects from envelopes.
One may eventually wind up in a collector's net elsewhere and make its own individual contribution to the database.
Source: Reuters
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