Monarch butterfly experts predicted a late migration this year, but taggers on the Llano River this weekend hit the jackpot with thousands of monarch butterflies arriving in what appears to be an early wave.

Near London, Texas, our tagging team encountered dozens of clusters of the iconic black and orange insects along the Llano River bottom this weekend.  The butterflies appeared stalled in the face of winds out of the south, which prevented them from continuing their migration to Mexico. They gathered in pecan trees in an area well-known for annual roosts, their gold and rust colored wings blending in perfectly with dried pecan leaves.

  • Monarchs cluster on pecan limbs. Photo by Lee Marlowe
  • Cacteye helps tag butterflies. Photo by Nicolas Rivard
  • Off she goes! Photo by Monika Maeckle
  • Monarch butterfly egg on swamp milkweed. Photo by Monika Maeckle

The winds from the south created an opportune tagging weekend for those on the butterfly hunt. Alexander Rivard, Nicolas Rivard and Lee Marlowe, all of San Antonio, joined me for net swoops of 10 -20 butterflies. Alexander Rivard hit a new record of 41 butterflies in one net swoop.

The 24-hour tagging talley: 325 butterflies.

In Hext, Texas, veteran tagger Jenny Singleton, chief docent for Grapevine’s Butterfly Flutterby Festival, witnessed the same large numbers.

Thousands of monarch butterflies took respite on the Llano River this weekend. Video by Nicolas Rivard

“Hundreds of butterflies are flying! So cool,” she texted earlier this week. “Easy to see because we have clouds.”

Singleton said she and her team tagged 250 butterflies in two hours on Saturday.

Journey North, which tracks the migration of monarch butterflies and other wildlife, posted a report from Del Rio, Texas, on October 5 that noted monarchs “roosting in clumps of two – six on huisache, hackberry and ash trees. Watching them stretch their wings when the sun starts to reach them is incredible!”

On iNaturalist, dozens of citizen scientists reported monarch butterfly sightings in Texas this weekend.

Interestingly, we also witnessed two courtship flights, as well as first instar caterpillars and eggs on late season swamp milkweed on the Llano River.

Peak migration season for San Antonio’s latitude occurs October 10 -22. Check peak migration for your latitude on the Monarch Watch homepage.

Plenty of chances to see monarchs continue throughout October in Texas, with a prime opportunity taking place next weekend at San Antonio’s sixth annual Monarch Butterfly and Pollinator Festival. More than 600 butterflies will be tagged and released at Confluence Park Saturday, October 16, 10 AM – 2 PM. Details here.

TOP PHOTO: Nicolas Rivard nabs a bag full of butterflies on the Llano River this weekend. Photo by Lee Marlowe, San Antonio River Authority

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