Eastern Tiger Swallowtail

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Taxonomy

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Papilionidae
Genus: Papilio
Species: Papilio glaucus

Common Names by Region

• Eastern Tiger Swallowtail
• Tiger Swallowtail
• Yellow Swallowtail (informal)
• American Tiger Swallowtail (less common usage)

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Description

General Form

A large, showy swallowtail butterfly with a wingspan typically ranging from 7.5–14 cm (3–5.5 inches). Recognized immediately by its bold yellow ground color and black “tiger” striping across the forewings.

Wings

• Forewings: Yellow with four prominent black stripes radiating from the leading edge.
• Hindwings: Yellow with black margins, iridescent blue scaling along the inner hind margin, and a small orange spot near the tail.
• Tails: Distinct swallowtail extensions, elegant and narrow.

Sexual Dimorphism

• Males: Typically bright yellow.
• Females: May be yellow (as in this image) or dark/black morph in some populations — the darker morph mimics the toxic Pipevine Swallowtail.

Underside

The underside is paler yellow with softer striping and visible blue and orange markings. When backlit, wings take on a translucent stained-glass appearance.

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Known Range

Widespread across eastern North America:

• Eastern United States
• Southern Canada (Ontario, Quebec)
• Extending south through the Southeast

Common in Pennsylvania and throughout the Mid-Atlantic.

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Habitat

• Woodland edges
• Open forests
• Meadows
• Gardens
• Roadsides

They are strong fliers and frequently move between canopy trees and lower flowering plants.

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Host Plants (Larval)

Caterpillars feed on a variety of trees, including:

• Tulip poplar (Liriodendron tulipifera)
• Wild cherry (Prunus spp.)
• Sweetbay magnolia
• Ash
• Birch

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Adult Nectar Sources

• Milkweed
• Ironweed
• Coneflowers
• Joe-Pye weed
• Hibiscus (as documented in this field image)

Adults are generalist nectar feeders and important pollinators in mixed-edge habitats.

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Propagation / Life Cycle

• Multiple broods per year in warmer climates (typically 2–3 in the Mid-Atlantic).
• Eggs laid singly on host plant leaves.
• Caterpillars resemble bird droppings in early instars (camouflage strategy).
• Later instars develop eye-spot patterns that mimic small snakes.
• Overwintering occurs in the chrysalis stage.

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Pests / Predators / Threats

• Birds
• Wasps
• Habitat fragmentation
• Pesticide exposure

Despite these pressures, the species remains common and stable across much of its range.

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Additional Notes

The Eastern Tiger Swallowtail is one of the most recognizable butterflies in eastern North America. Its size and coloration make it a flagship species for pollinator awareness.

The dark female morph represents an evolutionary response to predation, mimicking toxic swallowtail species — a classic example of Batesian mimicry.

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Field Notes (Image Documentation)

Location Context: Garden edge with flowering hibiscus.
Behavior Observed: Adult feeding on hibiscus bloom.
Lighting: Strong natural backlight producing translucent wing glow.
Sex Identification: Likely female, yellow morph (based on size and visible hindwing coloration).
Ecological Note: Hibiscus, while often cultivated, provides valuable nectar support for large swallowtails during peak summer activity.

This individual demonstrates classic underside patterning and intact tail structures — indicating good condition and likely recent emergence within the seasonal brood.

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Maintenance / Management

To support Eastern Tiger Swallowtails:

• Preserve woodland edges.
• Plant native host trees (especially tulip poplar).
• Avoid systemic pesticides.
• Include large-flower nectar sources such as hibiscus and native composites.

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