Before heading out into the field, you'll want to know what you're looking for. The resources below, including printable PDF guides, will help you learn to identify butterflies while in the field:

For more butterfly identification tips, watch this video from National Geographic:

 

Milkweed:

Milkweed is the only host plant of the monarch caterpillar. Utah's most prolific milkweed Asclepias speciosa, or "showy milkweed," can sometimes be confused with dogbane, which grows in many of our canyons and has much more delicate flowers.

A. speciosa (showy milkweed) — flowers May to July.

Photo by Rachel Taylor

Not milkweed — This is dogbane in bloom in Utah.

 

Distinguishing Characteristic #1

  • Umbrella-like flowering head (multiple flowers originate from one point like the base of an umbrella)

Distinguishing Characteristic #2

  • Milky sap called latex - visible when a leaf is torn

Caterpillars:

Signs of tiny monarch caterpillars eating the surface level of the leaf are usually accompanied by dark frass (poop). The larger the monarch caterpillar, the larger the frass. The consumption of the milkweed results in holes that go all the way through the leaf. Other damage to a leaf isn't as defined and lacks frass. Seed pods are also occasionally consumed by monarch caterpillars. During the heat of the day, the caterpillars often move to the base of the plant. Monarch caterpillars are black, yellow and white (except for right after they hatch).

Various sizes caterpillars and how they eat the leaves.

Photo by Rachel Taylor

Monarch caterpillar (late stage known as the 5th instar)

Photo by Rachel Taylor

 

Chrysalis:

A monarch chrysalis can typically be found on the same milkweed plant that supported the caterpillar throughout it's growth. However, a caterpillar can wander to adjacent plants or structures to find that perfect protective spot. The appearance of the chrysalis is green but turns dark soon before the monarch is ready to eclose (emerge).

 

Chrysalides (chrysalis, plural) in various forms. The monarch chrysalis has a green appearance for 12-16 days and then turns dark hours before eclosing (emerging). Photo by Becky Yeager