Monarch Joint Venture Blog
Eastern monarch overwintering population increases from last year
Numbers are in from Mexico, and it's good news. Monarchs occupied 2.93 hectares during the 2025-26 overwintering season, according to the survey from Telmex Telcel Foundation Alliance (WWF) and Mexico’s National Commission of Protected Natural Areas (CONANP). Read More
Western Monarch Count marks another low year at coastal overwintering sites
From late November through early December 2025, hundreds of volunteers and partners participated in the effort, surveying 249 overwintering sites and recording a peak population of just 12,260 monarchs. While this is a slight increase from last season's 9,119, it is the third-lowest tally since the count began in 1997. Read More
Monarchs arrive at overwintering sites while late-season sightings continue in the north
Monarchs have reached their overwintering sites right on schedule, even as a few late-season butterflies continue to appear across the northern U.S. Dr. Karen Oberhauser shares the latest migration observations, new tracking technology, and ways to support monarch conservation. Read More
Monarchs still on the move as calendar turns to November
As we turn the calendar, monarch roosts are being reported in Texas and Mexico, with the leading edge of migration near Saltillo in the State of Coahuila. The first monarchs should be arriving to areas near overwintering sites soon. Read More
Strong end to monarch breeding season; leading edge of migration reaches Oklahoma
Journey North volunteers have reported monarch roosts as far as Kansas and Oklahoma, and Dr. Karen Oberhauser writes that monarch observers with the Monarch Larva Monitoring Project reported monarchs in good numbers throughout August and into September. Read More