How to Tag Monarch Butterflies

Tagging Monarch Butterflies with Monarch Watch Tags (Please note the ESSENTIAL step below)

Monarch Watch tags should be applied in a specific manner. Reading and following the instructions that are included with your tags are important. Those instructions are far more important than the instructions on this page.

First, know how to tell a male from a female Monarch butterfly. Male butterflies have a black dot on their hindwings. Female Monarch butterflies do not. One of the columns on the data sheet that is to be returned to Monarch Watch registers whether the tagged Monarch butterfly is a male or a female.

Use caution when removing tags from the tag sheet and applying them to a butterfly. Oils from human fingers can prevent the adhesive from sticking to the butterfly’s wing. A toothpick, tip of a clean fingernail, paper clip, or other clean (not oily) item is recommended to apply the tag.

The discal (mitten shaped) cell on the outside of the hindwing is the appropriate spot to apply the tag. The tag can be applied to either the right or left hind wing. When the wings are closed, the tag should be visible.

IMPORTANT: Hold the butterfly gently and carefully. The butterfly can be held by the wings, close to the body. The abdomen should never be between the fingers. Monarch butterflies often pull their abdomens back between their wings. ALWAYS be gentle and determine where the abdomen is located before applying any pressure on the butterfly’s wings. Pressure on the abdomen will normally kill the butterfly. Use caution.

ESSENTIAL: After applying the tag, it is essential that we apply gentle yet firm pressure on the tag for several (three or so) seconds. This causes the glue to go THROUGH the scales to the wing. If this step is skipped, the tag will most likely come off the wing long before the butterfly reaches Mexico.

If one does not hold the tag firmly for several seconds, the tag will lift and fall from the butterfly. The first sign of lifting is normally a shadow on the wing under the tag, followed by the tag falling off. The wing will be missing scales and the back of the tag will be covered by scales. In a couple of the photos to the left, clearly the tag wasn’t held onto the wing long enough for the glue to go through the scales and adhere to the wing itself.

In spite of what we have been taught and what many of us have taught our children, a butterfly will not die if scales come off its wings. Because scales repel water, we should be careful, yes. It is best that most scales stay on the butterfly, especially since these are the generation that migrates to Mexico. Be gentle but please do not panic when some scales stick to your fingers. Butterflies often fly with half their wings missing. They aren’t as fragile as we imagine.

Last but certainly not least, be sure to return your data sheets to Monarch Watch. Tagging is of no value without returning your data sheet. If your tag is recovered, Monarch Watch needs the information your have recorded on your data sheet to know where the butterfly was tagged and who tagged the butterfly.

Happy tagging!

Monarch Watch instructions are here.

(A special thank you to Holli Hearn and my husband Stephen for tagging the Monarch in these photos for this webpage, including deliberately improperly tagging one to show what happens when one is tagged wrong. Holli’s facebook page is The Beautiful Monarch.)