A lesser-known migration of monarchs is arriving across Oklahoma and trackers of the butterfly population are interested in as many citizen sightings as people can offer.
“There is a group coming down from the north now and it’s the least-known part of the monarch migration phenomenon,” said Chip Taylor, research biologist and founder of the nonprofit Monarch Watch based at the University of Kansas.
With increasing publicity surrounding the dramatic decrease in the monarch population, many have come to know that monarchs have several generations and migrate from Mexico to as far north as Canada. But in recent years, researchers have learned the process is more complicated, with overlapping generations and a total of four distinct migrations each year, Taylor said.
Understanding those movements could help scientists help the population in the future, he said. The migration numbers should be fair this year, similar to last year, he said.
“One good thing this year is survival should be pretty good because there has been a lot of moisture so there should be a lot of fall flowers and plenty of nectar to help them on their border-to-border traverse,” he said
In the Tulsa area currently, summer-long resident populations that have gone through a few generations are laying eggs for a fifth generation that will fly off in mid-September for Mexico, but others are arriving from the north as part of the “mid-summer migration,” Taylor said.
The butterflies apparently make an initial move in August, prior to the well-known major migration that takes place in early autumn, he said.
“Directional flight” of monarchs across Kansas in late July has been monitored for years and reports of sudden influxes from Oklahoma and Texas followed, he said.
Some could stop in Oklahoma, but most likely will move through the state, settle in Texas and reproduce to create a fifth generation there.
A difference in the area now is that local monarchs likely appear older and “pretty beat-up” as they prepare to lay eggs and die, while the mid-summer migrators look “fresh,” he said.
Fifth-generation monarchs that appear in September are, on average, larger than their predecessors. While individual monarchs generally have a wingspan of 3 to 4 inches, the fifth generation will have more in the 4-inch range. It’s an adaptation presumed to allow the insects greater flight ability with larger wings for migration, overwintering and return migration in the spring, he said.
“There are reasons we don’t understand (for the earlier migration), but the potential is to get another generation in the south, or because if they stay to the north, the next generation might not get off in time ahead of cold weather.”
Extreme northern monarchs in the Ontario, Canada, region also are migrating into the Upper Midwest region now to lay eggs for fifth-generation monarchs that will pass through Oklahoma in September, he said.
“We need as many people as possible to tell us what’s going on and what they are observing,” he said. “That helps us get an idea of where the populations are robust and where they are not, how weather conditions impact them, what flowers are blooming and what is not, all of those things help add to our understanding.”
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Photo gallery: Rearing butterflies in Creek County
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