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Western Monarch Count

A male and female monarch rest on a branch in the sun in Santa Cruz (c. Diana Magor)
Western Monarchs Experience Average Winter Declines at Overwintering Sites
Monarchs aggregating on a tree at one of their overwintering sites
Despite a Lower Peak Season, Western Monarchs Start Spring in Higher Numbers than 2023
Cluster of monarchs on tree branches
Western Monarch Count Tallies 233,394 Butterflies
A cluster of overwintering monarchs
New Year’s Count of Western Monarchs Reveals High Seasonal Decrease Following Severe Winter Storms
Western monarchs overwintering in California 2021-2022 (Photo: Jessica Griffiths)
New Year’s Count of Western Monarchs Tracks Population Decline During Overwintering Season
Volunteers count monarchs in Pacific Grove Monarch Butterfly Sanctuary, December 2021 (Photo: Candy Sarikonda)
Western Monarch Thanksgiving Count tallies nearly 250,000 butterflies
Monarchs at a private overwintering site in Monterey county, CA
Monarchs at the Pacific Grove Butterfly Sanctuary in Pacific Grove, CA
The Bounciness of Butterflies
Graph showing results from surveys of overwintering monarchs in California. The number of monarchs has fallen for several years, so the height of the bars gets shorter and shorter to the right of the graph
Fifth Annual Western Monarch New Year’s Count Confirms Continued Decline in Western Monarch Population
A man and a woman stand nest to each other in front of a grove of old trees.
Remembering Bill Shepard, a Great Friend of Butterflies
"Western Monarch Thanksgiving Count Data 1997-2020 shows that despite a strong volunteer effort, monarch numbers are at the lowest point recorded since the count started in 1997"
Western Monarch Population Closer to Extinction as the Wait Continues for Monarchs’ Protection Under the Endangered Species Act
A handful of monarch butterflies with wings closed rest on the long gray-green leaves of eucalyptus
Monarch Population in California Spirals to Another Record Low
Monarchs stand close together on muddy ground on the edge of a puddle.
Monarchs stand close together on muddy ground on the edge of a puddle.
Monarchs Overwintering in Mexico Down 53%
A monarch with large pieces missing from both wings perches on an evergreen branch.
New Year’s Count Finds Continued Decline of Monarchs Overwintering in California
A monarch clings to the trunk of a tree in a dimly-lit landscape.
Thanksgiving Count Shows Western Monarchs Need Our Help More than Ever
In this close-up photo, a monarch perches atop a cluster of small, white and pink flowers. The image is so detailed, you can see the eye of the monarch, and the scales on its wings.
Monarch and Pollinator Habitat Kits Designed to Support Imperiled Western Monarchs
With wings spread, a monarch butterfly basks on a milkweed plant among the stems of a tulle marsh.
Western Monarchs: Notes from the Field
A group of scientists taking a photo together, including Emma Pelton, our monarch specialist.
Photo Essay: Trinational Monarch Meeting and Exploring Mexico’s Monarch Overwintering Sites
A western monarch rests on the side of a tree with furrowed bark.
New Year’s Count of Western Monarchs Confirms Decline, Trends Seen in Previous Years
A monarch clings to the trunk of a tree in a dimly-lit landscape.
Record Low Number of Overwintering Monarch Butterflies in California—They Need Your Help!
A monarch, with its wings folded, showing the duller orange side, clings to a rough tree trunk in a dimly-lit landscape.
Early Thanksgiving Counts Show a Critically Low Monarch Population in California
A bright orange monarch with a torn wing perches on some pink milkweed blossoms in a grassy, dry landscape.
Western Monarch Numbers Expected to Be Low this Year
A lone monarch in shadow perches atop fluffy, pink blossoms.
Very Low Numbers of Monarchs Overwintering in California may Reflect an Unusual Fall
Monarchs cluster on an evergreen tree branch.
2017 Monarch Numbers Are Down, Lengthening a Worrying Trend