Leonard Weber

March 22, 2023

Black Swallowtail is one butterfly that I can usually count on seeing frequently in Eliza Howell Park from mid-May to mid-September. Over the last 10 years, the average date of my first sighting of the year here has been May 18.

It is a large butterfly, with a wingspan of approximately 4 inches. Unlike many other species, the difference between females and males is easily recognizable.

As with most swallowtails, there are “tails” on the hindwings, not always easily seen. The spots are smaller on the female and, while the male sometimes shows a little blue, it is more extensive on the female.

Black Swallowtails are found in fields, parks, and sunny yards. As can be seen  from the photos, I usually see them in the park when they come to flowers for nectar.

Black Swallowtail is widespread in eastern United States.

The host plants for eggs and larvae are carrot family species. In vegetable and herb gardens, the caterpillars can be found eating parsley and carrot leaves. In the park, a favorite egg and larvae plant is Queen Anne’s Lace (aka Wild Carrot).

There are probably two broods a year in this area, and it is usually in September, near the end of the second brood, that I am most likely to see caterpillars. The caterpillar in the photo appears to be full-grown, over an in h long, ready to form the chrysalis. Black Swallowtail spends the winter in the chrysalis form, emerging as an adult in spring

While Black Swallowtail is a common butterfly of Eliza Howell Park, I am always excited to see these large and lovely insects. I will be looking for them in the middle of May