Butterflies at their winter home in Mexico. Butterflies at their winter home in Mexico.

Monarch butterflies are arriving ‘on time’

Millions are en route, according to several thousand volunteer butterfly spotters

The first monarch butterflies have arrived at their wintering grounds in the forest sanctuaries of the states of Mexico and Michoacán, the National Protected Areas Commission (Conanp) reported on the weekend.

While the first group arrived “in time” on November 1, 10,000 volunteer observers spread across 18 states including Coahuila, Nuevo León, Tamaulipas, Querétaro and Guanajuato have been reporting that millions of the migrating insects have returned to overnight stops identified last season.

“During this last five days we’ve received reports of large groups of butterflies. The first ones arrived on time to their sanctuaries . . . and we expect that the rest of the traveling groups will arrive within the next three weeks,” Gloria Tavera Alonso told the newspaper Milenio on Saturday.

The specialist explained that several cold fronts in the Gulf of Mexico may have delayed a few days’ delay for a some of these groups “but they have taken to the skies and thousands and thousands have been seen fluttering through Cuatro Ciénegas, Coahuila; the Monterrey hills, in Nuevo León; in Laguna Madre and the El Cielo biosphere reserve in Tamaulipas.”

Farther south, groups of monarchs seem to be converging as “even larger groups have been spotted in several areas in the state of Guanajuato: Celaya, Salamanca and Xichú, in the Sierra Gorda.”

This year is the second occasion on which Conanp has been aided by volunteer butterfly spotters. During the fall of 2015, volunteers located and identified for the first time the preferred places for the insects to spend the night and feed during their trip south. Some of those places were used by the migratory animals to protect themselves during the onslaught of Hurricane Patricia.

Not only do the monarchs have favorite resting areas, there are even trees they like better than others, said Tavera. For this reason, these zones have been strictly protected from logging activities.

Volunteers have also helped identify which roads intersect the butterflies’ migratory route. “Now we have signs informing motorists in those places,” said Tavera.

Flowers the insects feed on have also been identified, and that information is being used to promote the creation of pollinating gardens “that will allow them to recharge their energy.”

Conanp has yet to determine on what date the sanctuaries will open their doors to the public as the butterflies are given time to settle so as to minimize the impact of the presence of humans. Tavera estimated that by the 20th of November the first visitors will get the chance to see them.

Given that a winter storm hit the State of México and Michoacán forests earlier this year when the monarchs were leaving the country, fewer butterflies are expected this year than last.

It has been calculated that 140 million monarchs arrived on Mexican soil last season, covering over four hectares of forest. In the 2014-2015 season that figure was 255% lower: the insects barely covered one hectare.

Tavera expects that this season’s numbers will be just over half of last season’s.

Source: Milenio (sp)

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