Dreamy Duskywing

Erynnis icelus

Nine species of Duskywings have been found in Wisconsin. From a distance of 20 yards, without binoculars, they are all essentially indistinguishable little black skippers. On closer inspection, the Dreamy and Sleepy can easily be distinguished from the others by a lack of white spots in the forewing. Technically this is incorrect, as the Dreamy Duskywing sometimes has a single white spot, which is lacking in the Sleepy Duskywing, although this doesn’t mean that these species are then easily distinguishable from each other. Looking at photos online of these two species has given me many headaches and provided much confusion. I am sure that there are numerous photos online and in books of these two species that have been misidentified, which is understandable given how these two species resemble each other. In fact, I am certain that I myself have misidentified these species, assuming that the ones in central Wisconsin were just Sleepy Duskywings as I really didn’t notice any size differences, and the habitats that I found them in were similar.

Weekly sightings for Dreamy Duskywing

Identifying characteristics

A small black skipper, usually described as without white apical spots in the forewing above, but that sometimes does have a single white spot, and which holds it wings spread straight out while at rest. Above, there is a postmedian band of dark markings. Below this species has two rows of light spots on both wings. This species is best described as it compares to the Sleepy Duskywing (see the discussion below).

Similar species

In Wisconsin, this species should only be confused with the Sleepy Duskywing. In the field and in photographs these two species are very difficult to tell apart without experience with each species. Some differences include:

  1. The Dreamy Duskywing is smaller than the Sleepy Duskywing, a characteristic that is difficult at best without being extremely familiar with both species.
  2. The Dreamy has a more defined silvery light patch at the on the leading edge of the forewing, that is usually more obvious than in the Sleepy. This characteristic also varies greatly, and more worn Dreamy Duskywings may appear to have a less prominent silvery patch than fresh Sleepy Duskywings.
  3. In the Dreamy, the last segment of the palps is longer than in the Sleepy, a characteristic that also varies greatly and photos are not conclusive. There are many photos online of Sleepy Duskywings that appear to have very long palps (possible misidentifications?).
  4. In Butterflies of the East Coast, Cech and Tudor state that the Dreamy Duskywing has a single white spot near the leading edge, even obvious in the field, that is absent in the Sleepy Duskywing. This characteristic needs more scrutiny. As far as I know, Larry Weber (in Butterflies of the North Woods) is the only other author that mentions this characteristic. How did others miss this if it is so diagnostic? Is this characteristic of all Dreamy Duskywings, or just some populations? Not all photos of Dreamy Duskywings show this white spot — why?
  5. In many books, the postmedian bands of dark markings are referred to as “chainlike bands”. I had no idea what they were referring to until I discovered that in Howe’s 1975 The Butterflies of North America, he referred to this band having a “chain-linked” aspect. Thus the dark part of the bands can be thought of as representing the chain. This darker part of the bands is not as distinct in the Dreamy as it is in the Sleepy and usually the second, inner band is also more obvious in the Sleepy Duskywing. This seems to be the best characteristic to help differentiate fresh individuals of these two species, but worn individuals still pose identification troubles.
  6. The male Dreamy Duskywing has a hair plume on the hind tibia that is lacking in the Sleepy Duskywing. This characteristic is not very useful in the field, but may be of use to document this species from a photograph.

Habitat

Dreamy Duskywings host plants are mainly willows and poplar in Wisconsin, and as such are often found in moister habitats than the Sleepy Duskywing. But they can be found, especially when they are nectaring, in many of the same drier habitats where Sleepy Duskywings are found. In several other states, they may also use oaks as a host plants, so more study is needed to see if they may use oak species in Wisconsin.

Flight

One brood. Usually flies slightly after the Sleepy Duskywing, but both species fly primarily during May and June. Both species have been observed in April and in July in Michigan.

Abundance

Not usually seen in large numbers, and, like the Sleepy Duskywing, it is far more likely that you will see single individuals. However, they may become quite abundant in the far north of the state, where I have seen over 40 in a day.

Locations

Map showing sighting locations for Dreamy Duskywing
Map key
Dreamy DuskywingClick to enlarge

Sandhill Wildlife Area, Wood Co., WI, June 6, 2004.

Dreamy DuskywingClick to enlarge

Dunbar Barrens SNA, Marinette Co., WI, June 13, 2005.

Dreamy DuskywingClick to enlarge

Notice the plume of hairs on the hind tibia

East of Wazee Park, Jackson Co., WI. June 6, 2004.

Dreamy Duskywing

Beaver Creek Refuge, Eau Claire Co., WI. June 2, 2004.

Dreamy Duskywing

Beaver Creek Refuge, Eau Claire Co., WI. June 2, 2004.

Dreamy DuskywingClick to enlarge

Dike 17 Area, Jackson Co., WI, May 15, 2005.