Tagging Monarch Butterflies

We began tagging Monarch Butterflies in a effort to learn more about their migration patterns, life span, effects of weather, and the differences in migration from year-to-year.

With tagging we hope to also learn about migration routes and encourage conservation of habitats critical to the survival of the monarch butterfly and its migration. In 2012 over 200 Monarch Butterflies were tagged!

Preparing to tag Monarch. Applying tag to Monarch Determining if it is a male or female. It's a boy! tagged Monarch.


Existing data tells us that each latitude where Monarchs occur in the country has a peak migration time. Here on Mount Desert our latitude is 44.333N and Monarchs are migrating from mid August and September.

Monarchs farther south will begin their journey a few weeks later. Tagging and monitoring should begin in late August in all regions, with a concentrated effort made in September and early October. A rule of thumb is when the wild asters, especially A. novae-angliae, goldenrod and Joe Pye weed are in bloom, the monarchs are migrating. In much of the lower midwest, migrating monarchs are attracted in large numbers to a tall late blooming thistle (Cirsium altissimum) several species of sunflowers and other species of Asteraceae.

Information is collected when tagged Monarchs are observed or found along their migration route and then compiled into a national database. Since 1994 over 11,000 Monarch Watch tag recoveries are now accessible via a searchable database.