The Eastern Tiger Swallowtail (Papilio glaucus) is a common type of butterfly found in Eastern North America. They are a native species with a range from east of the Mississippi to parts of the Great Plains region. They have also been found in parts of Mexico and Canada. Often solitary, these arthropods are most active during hot temperatures.
Eastern Tiger Swallowtail Appearance:
As Caterpillars:
The caterpillar of the Eastern Tiger Swallowtail appears in five forms or instars during its development. First, they appear as brown with a white abdomen. In this form they resemble bird droppings. They molt three more times. In the fourth instar, they become green with faux eyes which makes the caterpillar look more like the head of a green snake. These mimicry tactics are meant to disguise the young caterpillar from potential threats. If the disguises fail, and a predator attempts to interact with the swallowtail larvae, the caterpillar will use two orange glands to emit a noxious odor. In the fifth and last instar, the caterpillar becomes brown before it pupates.
As Butterflies:
The Eastern Tiger Swallowtail has a wingspan ranging from 3 to 5.5 inches. Males only appear with yellow wings that have the characteristic four black stripes which give off the tiger-like appearance. On the other hand, Females can come in two forms. Females appear in either yellow or black. As the yellow form they are similar to males except their bottom possess a prominent band of blueish scales. Males lack this bluish hue and usually have only a black band at the bottom edge of their wings. Females also possess red scales at the bottom.
Eastern Tiger Swallowtail Diet:
While solitary, male eastern tiger swallowtails will congregate around damp sources to drink, in a behavior called “puddling.” As larvae, the swallowtails eat leaves of deciduous trees and other woody shrubs and plants. As butterflies, swallowtails drink nectar.
Preferred types of food sources include:
| As a Caterpillar | As a Butterfly |
| Wild Cherry | Wild Cherry |
| Ash Tree | Milkweed |
| Tuli Tree | Dandelion |
| Birch | Honeysuckle |
| Willow | Lilac |
Metamorphosis:
The process of a caterpillar changing into a butterfly is called metamorphosis. At this final stage, the caterpillar appears brown. As it begins the process of pupating, the caterpillar will find a place to cling to, usually a tree trunk, fence post, or under a leaf. It will form a chrysalis and appear whitish or brown. This will occur during the winter. Afterwards, they will emerge as the butterfly.
How to Attract the Eastern Tiger Swallowtail:
If you would like to invite these beautiful butterfly specimens to your garden the best tactic would be to plant welcoming host plants. These include the preferred sources of food listed above for the butterfly form. But you can also find your native plants in your region that are deemed butterfly friendly especially if they are coneflower, phlox, and ironweed types. They prefer pink or purple flowers so finding a variety in this type may help with attracting the butterfly. Adding a source of water could help as well but be careful not to attract mosquitoes that like still water or birds that prey on the swallowtail.
Sighting:
I spotted an Eastern Tiger Swallowtail in two places. First on my balcony where I had planted pink coneflowers. The second time was at the Untermyer Gardens Conservancy in Yonkers, NY. It was a hot day at the gardens. I was making my way around when I came across a bed of flowers. While the plants were yellow and orange, I noticed a familiar winged friend fluttering from petal to petal. It turned out to be another Eastern Tiger Swallowtail. Because both had the blue coloring, I believe they were both female specimens. After seeing this butterfly, I made my way on the trail that leads near the Old Croton Aqueduct which was touched upon in my Tibbetts Brook Park post.
Species Spotlight:
| Common Name | Eastern Tiger Swallowtail |
| Scientific Name | Papilio glaucus |
| Location Spotted | Untermeyer Garden, Yonkers, Westchester County, New York |
| Date Spotted | July 21st, 2023 |
| Sighting and Trail Remarks | While visiting the Untermyer Gardens, I came across an Eastern Tiger Swallowtail in a bed of orange and yellow flowers. The gardens have a variety of plants which makes for a welcoming experience both for visitors and butterflies. A trail is under construction that goes by the Old Croton Aqueduct and offers a peaceful stroll. |