Eastern Tiger Swallowtail

Pterourus glaucus

Copyright, Jay Cossey: http://www.images.on.ca/JayC/jc_g1index.htm

The Eastern Tiger Swallowtail, along with the Monarch, is one of our most recognizable butterflies. You can identify it (usually) by its large size and bright yellow color with black tiger stripes.

Male tiger swallowtails have a few orange and blue spots near the tail.

Females have both a light and dark form. Believe it or not, the picture to the right and the picture directly below are both female Eastern Tiger Swallowtails! The light form (below) looks a lot like the male, except it has more blue on the hind wings. The dark form still has the blue spots, but it is otherwise very dark with no yellow.

Johnson County K-State Research and Extension Master Gardener, Jacolyn Loyd Goetz

Mark Moran

Johnson County K-State Research and Extension Master Gardener, Jacolyn Loyd Goetz

After mating, female tiger swallowtails lay eggs on leaves of host plants. Host plants are the plants that caterpillars will eat. Host plants of Eastern Tiger Swallowtails include Yellow Poplar, Black Willow, Black Cherry, American Hornbeam, Red Maple, Spicebush, American Elm, and Sassafras.

When caterpillars first hatch, their colors look a lot like bird poop. This helps camouflage them. As they get older, they turn green with a large head and bright eyespots. The eyespots aren't really eyes. They are probably there to scare away predators, or to make them attack the wrong part of the butterfly. A butterfly can lose part of a wing and still survive.

Johnson County K-State Research and Extension Master Gardener, Jacolyn Loyd Goetz

Johnson County K-State Research and Extension Master Gardener, Jacolyn Loyd Goetz

Johnson County K-State Research and Extension Master Gardener, Jacolyn Loyd Goetz

Bill Dunn, Huntley Meadows Park

When caterpillars are fully grown, they will then become pupae (resting stage). The name for a butterfly pupa is chrysalis.

An adult Eastern Tiger Swallowtail will come out of the chrysalis in a couple of weeks. If the weather is getting cold, the butterfly might wait until the following Spring to emerge.

The chrysalis of this butterfly is greenish-brown, and a little over an inch long.

Eastern Tiger Swallowtails are found all over, especially near water, but also in meadows, gardens, parks, and roadsides.

Adult Eastern Tiger Swallowtails drink nectar from flowers. They visit many plants, both wild native plants and garden flowers. Some of those flowers include milkweed, thistles, Japanese Honeysuckle, Ironweed, and Red Clover.

This butterfly has many bird predators. Other animals will eat caterpillars, including squirrels, Raccoons, and shrews.

A dark female Eastern Tiger Swallowtail mimics another butterfly called the Pipevine Swallowtail. Mimicry is when one animal looks just like another animal in order to gain safety or some other advantage. Pipevine Swallowtails eat a plant called Pipevine which makes them taste nasty to predators. Predators will learn to leave them alone. The dark female Eastern Tiger Swallowtail will also get left alone since it looks like a Pipevine Swallowtail, even though it is good to eat! Female tiger swallowtails will only have the dark form if a lot of Pipevine Swallowtails live in the same area. However, there will still be some light form females as well.

Mark Moran

Additional Media

Butterfly Anatomy Diagram
Link to Printable Page

Relationships in Nature:


Yellow Poplar

Great Crested Flycatcher

Yellow Poplar

Pipevine Swallowtail Mi

Black Willow

Red-winged Blackbird

Black Willow

Japanese Honeysuckle Po


White-breasted Nuthatch


Common Milkweed Po


Eastern Gray Squirrel


Bull Thistle Po

Red Maple

Virginia Opossum

Red Maple

Ironweed Po

American Elm


American Elm

Red Clover Po

Black Cherry

Common Crow

Black Cherry

Spotted Joe-pye Weed Po

Common Milkweed

Belted Kingfisher

American Hornbeam

Black-eyed Susan Po

Bull Thistle

Green Darner

Japanese Honeysuckle

Barred Owl


Chinese Mantid

Red Clover

Fiery Searcher

American Hornbeam

Downy Woodpecker

Spotted Joe-pye Weed

Bald-faced Hornet

Black-eyed Susan

Sharp-shinned Hawk

Relationship to Humans:

Eastern Tiger Swallowtails are appreciated for their beauty, and many people plant flowers to attract them, as well as other butterflies. Swallowtails also help pollinate flowers.


Pterourus glaucus


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