Leonard Weber

June 10, 2024

One butterfly that regularly appears in Eliza Howell Park in June is Hackberry Emperor.

It is somewhat small (wingspan of about 2 inches), flies swiftly and alights frequently – on the ground, on trees, sometimes on people.

It frequently opens its wings when perched, but it is also possible to get a view of it with the wings closed.

Over the years, I have been able to  observe not only when Hackberry Emperor first appears each year, but also where in the park I am most likely to see the species.

I often find it on or near the foot bridge over the Rouge River.

I have been seeking to understand why they are found so frequently around the footbridge at this time of the year. Perhaps it is a combination of two factors.

A. Hackberry Emperor butterflies are reported to be attracted to bright colors. If so, they would likely find the painted railings of the footbridge very inviting.

B. The second factor relates to the butterfly’s life cycle. Hackberry Emperors lay eggs on hackberry trees and the caterpillars eat hackberry leaves. The caterpillars from the second brood are about half grown when fall comes. They pause their growth, spend the winter as half-grown caterpillars (in diapause), and finish development when the hackberry has new leaves in the spring.

The butterflies begin to emerge from the chrysalis stage in early June. In heading for a more open area of the park (the hackberry trees tend to grow in the heavily wooded area), the butterflies cross the river. The footbridge provides a pathway.

Whether my possible explanation is  accurate or not, Hackberry Emperor butterflies can often be seen at this time of the year on the footbridge and along the gravel path that goes from the road to the river.

Hackberry Emperor butterflies have been quite numerous so far this June. I am getting so accustomed to seeing them on or near the footbridge that I am, for the first time in all these years, starting to use a name when I think of the foot  bridge.

It is the Hackberry Emperor Bridge.