Tagging a Monarch Butterfly–Tracking the Migration

Butterfly tagging on September 11, 2001

About the photograph

I photographed this on September 11th. In addition to the horrible events of the day, I remember spending the day with a Biologist friend in New Hampshire tagging Monarch Butterflies. He had been tagging them for many years and had several reported from Mexico.

Why Tag Monarch Butterflies?

Tagging helps scientists track monarch migration, understand survival rates, and identify important stopover sites. Data collected from tagged butterflies contribute to conservation efforts.

How to Tag a Monarch Butterfly

Tags are available from organizations like Monarch Watch (www.monarchwatch.org), which provides small, lightweight stickers with unique identification numbers.

Handle the Butterfly Properly

Gently grasp the monarch by the wings, keeping them closed.

Hold the butterfly at the thorax to avoid damaging its wings.

Place the Tag

The tag should be applied to the discal cell on the hindwing, which is the large, central cell near the body.

Press gently but firmly so it adheres properly.

Record Data

Note the following information:

Tag ID number

Date of tagging

Location (city, state, GPS coordinates if possible)

Sex of the butterfly (males have two black spots on their hindwings; females do not)

Condition of the butterfly (fresh, worn, damaged)

Release the Butterfly

Let the butterfly rest on your hand or a flower until it flies off naturally.

Best Time and Place to Tag

Timing:

In the U.S., tagging typically occurs late summer to early fall (August–October) as monarchs migrate south to Mexico.

Location:

Ideal tagging sites include fields with milkweed and nectar flowers, where monarchs feed before migration.

How Data is Used

If a tagged butterfly is recovered (often in Mexico), the finder reports the tag number to Monarch Watch.

Researchers use this data to study monarch survival rates, migration speed, and environmental influences on their journey.

Citizen Science Participation

Many organizations encourage public involvement in monarch tagging. Schools, nature centers, and individuals can participate by ordering a tagging kit and reporting data.