2021 Bitterroot Monarch Project Update

The Bitterroot Monarch Project continued its third season documenting monarch presence across the
northern Bitterroot Valley from Missoula to Stevensville. We found eggs and larvae at 6 locations this
year: Maclay Flats, private property neighboring MPG Ranch, and 4 sites on MPG Ranch. MPG Ranch
consistently provided safe breeding habitat for migrating monarchs each year. We collected all eggs and
larvae found on MPG Ranch for captive rearing and found no evidence of either parasitoid flies or the
protozoan parasite OE. We raised 23 butterflies, the highest number to date, and released them with
identifying sticker tags. The project contributed 41 genetic samples to a Colorado State University study
that aims to untangle questions of population connectivity and migratory behaviors.