Monarch butterfly numbers in Mexico drop again

The number of monarch butterflies wintering in Mexico dropped by 27 percent this year, reversing last year's recovery from historically low numbers, according to a study recently released by the government and independent experts.

The experts say the decline could be due to late winter storms last year that blew down more than 100 acres of forests where migrating monarch butterflies spend the winter in central Mexico.

Millions of monarchs make the 3,400-mile migration from the United States and Canada each year, and they cluster tightly in the pine and fir forests west of Mexico City.

Officials estimate the storms in March killed about 6.2 million butterflies, almost 7.4 percent of the estimated 84 million that wintered in Mexico, said Alejandro Del Mazo, Mexico's commissioner for protected areas. The monarchs were preparing to fly back to the U.S. and Canada at the time the storm hit.

While no butterfly lives to make the round-trip, a reduction in the number making it out of the wintering grounds often results in a decline among those who return the next year.

In addition, the fight against illegal logging continues. Authorities recently detained a man trying to truck about a dozen huge tree trunks out of the butterfly reserve, using false papers asserting the trees were diseased and were being removed to reduce risk. In fact, investigators found the trees had been healthy.