Help us learn more about monarch butterflies during the fall migration!

EXPANDED FALL TAGGING PROTOCOLS

The goal of this project is to collect additional information about monarchs during the fall migration. We measure wing length and wing width to get an estimate of wing size which reflects conditions during larval development and can influence migration success. We record body weight since the combination of body weight and wing size provides information about body condition. We test for Ophryocystis elektroscirrha (OE), a spore-forming protist that negatively impacts monarch migration success and survival, to get a better idea of OE prevalence. And lastly, we tag the monarchs with a Monarch Watch tag and release them. The tagging contributes to a long-term community science project that collects information about the timing and pace of the migration, and the source of monarchs at the overwintering sanctuaries in central Mexico.

EQUIPMENT/MATERIALS NEEDED

• Monarch Watch tagging kit

• Datasheets (make sure you use the 2026 Tagging Datasheet for the expanded tagging protocol that includes a column for mass and a space for the OE sample, see below)

• Insect net for catching monarchs

• Ruler (with mm scale) for measuring wing length; a mm ruler is included in the Monarch Watch tagging kit

• Scale (with measurement to 0.01 grams or 0.001 grams if possible) for weighing monarchs; you can find jewelry or pocket scales on Amazon for about $20

• Glassine (wax paper) envelopes for weighing monarchs and collecting monarchs for bulk processing

• Clear mailing seals (Avery® #5248) for testing for OE

• Box or cooler to use as a wind barrier for your scale if you are processing your monarchs outside

• Educational sheets if helpful

Note: The 2026 Tagging Datasheet - Expanded Version is a single-sided letter-sized datasheet designed to accommodate up to 5 records of monarchs released from a single location. When printing, please use standard white 8.5x11" paper and be sure to print the sheet at 100% of its original size so the mailing seal (OE sample) fits inside its cell.

PROCEDURE

Step 1: Catch a monarch!

To remove it from the net, gently hold the monarch at the base of its wings near its body. If you want to catch several monarchs to process at once, you can place them in glassine envelopes. It is easiest to put them in feet first.

Keep track of the activity of each monarch so that you can record that information on the datasheet. In many cases you may be catching monarchs that are all doing the same thing (e.g., nectaring), so you could add a note to the glassine if you have one that is doing something different. You will also need to record if your monarch is wild-caught or reared ("origin" on the datasheet), so keep track of that information as well.

If you use the batch processing approach, make sure to keep your monarchs in a cool place until you process them. If you use a cooler, make sure they don't come into direct contact with ice or moisture. If you place in a refrigerator, place in the door or near the front where it is warmer.

Step 2: Identify if you have a male or female monarch.

Males have a pouch on the hind wings that is not present in females. Males also have claspers at the tip of the abdomen whereas females have a notch near the tip of the abdomen.

Step 3. Measure the length and width of the right forewing.

Use calipers or a ruler to measure the length and width of the right forewing. If the right wing is damaged, you can measure the left. The numbers should be reported as two digits (e.g., 50mm).

Wing length is measured from the white spot at the base of the front wing to the tip of the wing. The white line represents the measurement.

Wing width is measured perpendicular to the leading edge of the wing (red line). The white line represents the measurement.

Step 4. Weigh the butterfly.

Adult monarchs are weighed in glassine envelopes. The scale needs to be tared (set to zero) with the envelope first before placing the butterfly feet first (helps keep them from escaping) in the envelope for weighing.

Place the monarch in the envelope and record the mass as X.XX g (e.g., 0.57 g) or X.XXX if the scale goes to three decimal places.

If you are weighing your monarchs outside, you will need to find a stable location for your scale. It often works well to place a cooler or bucket on the ground and place the scale inside to eliminate issues with wind.

Step 5. Record wing damage and scale loss scores.

Step 6. Collect a sample to be evaluated for OE spores.

The round mailing seals (clear stickers) are used for sampling for OE. Hold the monarch near the base of its wings so that the abdomen is extended and available for sampling. Gently press a mailing seal against the ventral (bottom) side of the abdomen. The tape will remove scales, which the butterflies lose naturally, as well as any OE spores, if present. An outline of the abdomen should be visible on the mailing seal. Place the mailing seal on the datasheet. If the sample is faint, re-apply the mailing seal until the sample is adequate.

Left to right above: Hold the monarch so it extends its abdomen. Gently press a mailing seal on the monarch's abdomen. Confirm that you have a good sample and place on the datasheet.

If you have access to a microscope, you can see if your sample has OE. An OE infected monarch will have OE spores interspersed among the scales from the abdomen. Infected individuals may have anywhere from a few spores to thousands of spores, so you check carefully.

 

There is sometimes debris in the sample, or ink dots from printing or copying the datasheet, but you can distinguish the OE spores by their distinct shape, which is often referred to as football- or lemon-shaped. The OE spores are also very dense and solid in color.

Step 7. Tag the monarch with a Monarch Watch tag.

• Carefully hold a monarch between your thumb and index finger along the leading edge of the butterfly's forewings (close to the body, not the tip) and locate the discal cell (large mitten-shaped cell on hindwings). See figure below for guidance.

• Record all data before removing a tag from the sheet.

• Remove a tag from the sheet by its edge (a toothpick might be helpful), place it over the discal cell of either hindwing and carefully apply pressure to the tag from both sides of the butterfly (see figure below for placement) using your fingers. Press firmly for several seconds and release the butterfly — again, making sure all of the information is recorded first!

• Try not to allow the tag to stick to any other surface, such as your finger, before applying it to the butterfly — to be most effective, the adhesive on the tag must be clean when applied to the wing. The tag cannot be moved once placed, so don't try to adjust the location of the tag.

• Tip: If you are tagging in the same location over multiple days, you can tag the same side each time so it is easier to identify if monarchs are already tagged.

Step 8. Check over your datasheet and make sure that all fields are complete.

Step 9. Release your butterfly!

Step 10. Send in your data!

We need your original datasheets with the mailing seals to score the OE sample. You may want to make a copy of your datasheets for your records. Mail your datasheets to:

Monarch Watch
University of Kansas
2021 Constant Ave
Lawrence, KS 66047