Last week, I wrote about the bad news: that monarch butterfly populations have been plummeting since the 1980s. The good news is that a revolutionary new tracking device may help those populations recover.
Naturalists have been trying to track monarchs for nearly a century, but mass ID-ing (with tiny stick-on tags) only began in large numbers in 1992 by the nonprofit Monarch Watch, based at the University of Kansas. Now more than 100,000 monarchs are tagged annually in the fall before the southbound migration begins, with up to five percent subsequently recovered. The problem with tagging has been likened to reading the first and last pages of a book: You miss everything in the middle.
That’s all changing with the introduction of tiny solar-powered Bluetooth transmitters. “It’s an incredible technological advance,” according to Chip Orley, founder of Monarch Watch, quoted in a recent New York Times story. The challenge was to create a super-light transmitter that could be attached to migrating monarchs without impeding their flight. How light? An adult monarch weighs 600 milligrams, and burdening it with much more than a tenth of that could doom the creature’s long migration.
A private firm, Cellular Tracking Technologies (CTT), met the challenge. After several breakthroughs in nanotechnology over a decade, they came up with a 60-milligram “BlūMorpho” transmitter, weighing about the same as three grains of rice. The tiny instrument, complete with a short antenna, can be glued to a monarch’s thorax with essentially no effect on flight. “They might be moving a little slower,” according to Leone Brown of Virginia’s James Madison University. A butterfly’s wings are held in glassine sleeves for protection and weighted down to prevent fluttering prior to attaching the transmitter with eyelash adhesive. (Previous attempts using epoxy killed the unfortunate creatures.) After providing hundreds of transmitters free or at cost to conservation organizations, CTT is now making them available to butterfly lovers for about $200 each.
This past year has been a golden one for monarch butterfly lovers and researchers. In a stunning proof of concept in November of 2024, a network of crowd-sourced smartphones automatically tracked a newly-tagged monarch named Lionel from Cape May Point in New Jersey to Florida. BlūMorpho transmitters have a range of about 300 feet, so with hundreds of volunteers having the “Project Monarch Science” app on their smartphones, Lionel was tracked all the way in real time. Following on this initial success, first dozens, then hundreds, of transmitters were deployed last fall on monarchs leaving from all over the Eastern U.S. and adjacent parts of Canada destined for groves in central Mexico. Thousands of volunteers with smartphones are now automatically tracking their migrations in real time.
By knowing in detail the migration routes taken by the monarchs, the hope is that milkweed and energy-rich nectar plants will be cultivated in critical locations to facilitate the migrations, while more areas will be set aside as refuges. With dedication and a great deal of luck, this huge effort by individuals and nonprofit organizations will lead the way to restoring monarch butterfly populations to their previous hundreds of millions of individuals.
Barry Evans (he/him, barryevans9@yahoo.com, planethumboldt.substack.com) notes that the name “monarch” was given in honor of the Prince of Orange, King William III of England.
This article appears in Granny Rage on Women’s Day.