Common Illinois Butterflies

Fun fact: Illinois butterflies constitute less than ten percent of the total Illinois Lepidoptera population. Of the approximately 2000 butterfly and moth species in the state, about 150 of them are butterflies.

Fans of the Lepidoptera population continue to have multiple choices for their species identification goals. In the butterfly group, for example, around sixty five species get placed in the skipper butterfly category and a subset of butterfly fans focus on identifying them. The video at the top of the page, for example, shows the Silver-spotted skipper, one of the most wide ranging skippers in the United States.

It’s larger than average size along with the distinct wing markings on both the top and bottom of the wings make it easy to identify. Otherwise, as a group, the skippers tend to be the most difficult group to identify because they share similar physical characteristics of brown wing shades with different lighter patterns on the wings.

Skipper enthusiasts at the Illinois Butterfly Monitoring Network cover the state and suggest six additional regional skipper butterflies that are also common across all or almost all of Illinois.

• Zabulon Skipper
• Least Skipper
• Tawny Edge Skipper
• Peck’s Skipper
• Fiery Skipper
• Wild Indigo Duskywing

They also suggest taking a few moments with the camera to obtain pictures of both wing tops and bottoms to help with identification.

Taken as a whole, the more colorful butterflies are much easier to identify, due mainly to the fact that originally physical features such as wing color and patterns grouped butterflies by family. Recent DNA research does help clarify identification in a few genera where species and subspecies identification causes confusion.

This introduction to Illinois butterflies provides identification tips for species in the remaining butterfly families based on physical characteristics.

Populations of different species will differ slightly from area within the state. In the greater Chicago area, for example, butterfly gardens can sprout up almost anywhere because the larvae or pupa of about twenty different species overwinter, ready to transform into butterflies as the warmer weather moves in. The Silver-spotted skipper in the video is one such butterfly.

Visitors interested in additional butterfly video, pictures and identification help can press the green butterfly button for more information.

Illinois Butterflies – Brush-footed Butterflies

The large and colorful wings of many brush-footed butterflies make them back-yard garden favorites. One such butterfly, the popular Monarch Butterfly, pictured, is the state’s official state butterfly.

State wide action continues to be taken to reverse the downward pressures on local Monarch populations. Recent estimates suggest the populations have decreased as much as eighty percent over the past few decades. Public and private sector actors continue to promote the use of Milkweed in the garden to provide larval host plants.

Fritillary and lady butterflies also fit the large and colorful Brush-footed butterflies group. Keep an eye out for the Painted Lady in the picture. It is one of the most common butterflies in the world, often refereed to as the Cosmopolitan butterfly. Its global range can be attributed to the fact that the caterpillars are not picky eaters and will feed from many host plants.

The group of butterflies with common names such as wood-nymph and satyr can initially be identified by a wing color with various shades of brown. The presence of eye-spots on the wings makes identification fairly straight forward.

It’s also interesting to note that whether one visits Chicago in the North or the Shawnee National Forest in Southern Illinois, there will be a fairly decent wood-nymph presence. The picture shows a Little wood-satyr.

Comparing the size of different brush-footed butterflies also helps the identification task move forward. Checkerspots tend to be medium sized butterflies with wing spans less than the milkweed and lady butterflies. Small size and the presence of large dark wing borders contrasting with the orange wing color make them fairly easy to identify.

Milbert’s tortoiseshell

Mourning Cloak

Butterfly chrysalis come in a handful of shapes. Often they can be found attached to grasses and small twigs.

Butterflies: Whites and Yellows

Pieridae is the formal name of the family that consists of the butterflies with white wings and yellow wings.

Yellow butterflies dominate the Illinois butterfly list. The Clouded Sulphur and Cloudless Sulphur are probably the most common yellow butterfly species in the north, including the Chicago region.

The picture shows a cloudless sulphur butterfly.

Orange Sulphur

Sleepy orange butterfly wing color can change shades depending on the season. The side view shows a darker shade, indicating the transition to a fall or winter form.

It should come as no surprise to anyone that Cabbage White butterflies are the most common white butterflies in Illinois. Their caterpillars feed on plants from the cabbage family.

Checkered white butterflies also feed on plants in the cabbage family. The white winged butterfly in the picture is the male.

Olympia Marbles are small butterflies of prairies and open forests. Larvae feed on a few plants in the mustard family. They are early bird butterflies, flying for only one month in the year.

Blues, Hairtreaks and Coppers

General physical feature identification rules exist for members of the Lycaenidae family, best known by their common names, blues hairstreaks and coppers. Blue butterflies generally have blue wings. Hairstreaks generally can be identified by the presence of protruding hairs on the bottom of their tails. Copper butterflies generally have copper color wings.

As rules of thumb, they work fairly well for initial butterfly identification. There are also exceptions to the physical identification rules for a few of the species.

Consider the picture of the Harvester butterfly at the top of this section. Copper color wings and the lack of protruding hairs might suggest a copper butterfly. It’s actually the only species in the Miletinae subfamily, and related to all three other groups. Finding one in the garden provides an extra bonus because their caterpillars , unlike all other butterflies in the United States, feed on aphids rather than plants.

The picture shows a Bronze Copper. They can most often be found near areas with water, including roadside ditches and ponds across the state.

The Eastern Tailed-blue and Azures are the most common of the Illinois blue butterflies. Mostly because their larvae have flexible diets of common plants such as peas. Eastern tailed-blues also go against the standard identification rules of thumb for the group because of the presence of protruding hairs on the bottom of the wings, similar to the hairstreaks.

The picture shows a Summer Azure, fairly easy to identify by the chevron markings on the wings.

Eastern Tailed-blue

Gray Hairstreaks might look similar to Eastern tailed-blue butterflies. They are smaller.

Like most states, Illinois has a large number of hairstreak butterflies. They are the ones with the small extension or tail feature on the wings.

Most of the species are regional oriented. The Gray Hairstreak bucks that trend and is the most common hairstreak species in the United States. Gray Hairstreak top view

The picture shows a Banded Hairstreak. They are very common in the eastern part of the United States. Their larvae consume leaves on a few common trees such as oak, walnut and hickory.

Butterflies: Swallowtails

The picture shows an Eastern Tiger Swallowtail. They are very common because a variety of trees such as apple trees and cherry trees serve as larval hosts.

Since they are basically the only swallowtail species in Illinois with yellow wings, identification is fairly straight forward. There’s always a catch. Some females have a dark form. They can be identified by the absence of white spots on the abdomen.

Pipevine Swallowtails might be the least common in Illinois. Zebra Swallowtails can be found wherever the Pawpaw tree grows. It’s the larval host tree.

• Pipevine Swallowtail
• Zebra Swallowtail
• Black Swallowtail
• Eastern Tiger Swallowtail
• Spicebush Swallowtail
• Giant Swallowtail