San Diego

Agency Sees Decline in Migrating Monarch Butterflies

A drastically low number of western monarch butterflies have been recorded this year along the California coast, according to a volunteer agency that organizes a count of the creature each winter.  

Xerces Society for Invertebrate Conservation sends a team of volunteers spanning the California coast for three weeks each Thanksgiving to collect data on western monarchs who will soon journey south for the winter before migrating back north for the spring. 

This year, the agency noted the early results of their count were "disturbingly low." 

While the results won't be finalized until late January, Xerces Society said the locations they had recorded so far -- which accounts for 77 percent of the total migrating monarch population -- saw an 86 percent decrease this year from last. 

The count has been taken every Thanksgiving since 1997 at various spots along the coast between Baja, Mexico and the Bay Area.

The World Wildlife Fund, which tracks the butterflies' populations in Mexico in coordination with the Telmex Telcel Alliance, found a 15 percent decline from 2017 to 2018 and an 86 percent in the last two decades. 

See Monarchs Year-Round at Encinitas Butterfly Farms

Pat Flanagan, the director of Butterfly Farms in Encinitas, said in late July, visitors started complaining they weren’t seeing as many monarchs in their wildlife areas.

"A lot of our historic customers were coming in and saying hey- I don't have any monarchs. I've always had monarchs, and this year, for whatever reason. We say, just wait, they're gonna show up. But in some cases, that didn't happen," Flanagan said. 

Monarchs are some of the longest-living butterflies and they have been considered a migratory phenomenon -- the only non-bird species that travel thousands of miles in two directions each year. 

The WWF said because the monarch butterfly's migration coincides with weather conditions, climate change threatens to disrupt their migration and colder winters and warmer summers could contribute to population decline.

"Most people don't understand that the monarch, like so many of the insects, they have a symbiotic relationship with the plant world," Flanagan said. "They're connected to the plant world and so when we're not seeing them, we have to question what's going on in the plant world." 

A 2014 petition to the U.S. Fish and Wildlife Service (USFWS) asked the agency to consider adding the monarch butterfly to the Endangered Species List.

USFWS is in the process of evaluating whether the species should be federally protected and a decision is due by June 2019. 

Those that want to help the monarch butterfly can help by creating monarch habitats, planting native gardens and helping scientists track the species, to name a few. More ways to help can be found on the USFWS "Save the Monarch Butterfly" website.

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