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New Jersey Endangered and Threatened Species Field Guide

Image of Sleepy duskywing.Zoom+ Sleepy duskywing. Photo courtesy of Wade Wander.

Sleepy duskywing

Erynnis brizo

Species Group: Invertebrate

Conservation Status

State: Special Concern



The upperside of the sleepy duskywing is brown and the forewing has two wide gray bands and no transparent spots. Male has a fold containing yellow scent scales, while the female has a patch of scent scales on the 7th abdominal segment. The antennae of the sleepy duskywing are very blunt. This species has a wingspan of 1 ¼ to 1 ¾ inches.

Image of Range of the sleepy duskywing in New Jersey.Zoom+ Range of the sleepy duskywing in New Jersey.


Sleepy duskywing populations range from California in the west to Utah and southern Wyoming in the east; south through the mountains to Arizona, New Mexico, Baja California Norte and central Mexico. In the east, from Manitoba south through southern Ontario and the eastern United States to central Florida, the Gulf Coast, and central Texas. It is very local and uncommon in northern New Jersey, but somewhat more common within the southern portion of the state, particularly within the Pine Barrens.

The sleepy duskywing uses oak or oak-pine scrub, as well as chaparral and barrens. They are often found on well-drained sites with sandy soils. Sleepy duskywing is very habitat-specific in its distribution.


The caterpillar of this species often uses scrub oak and other shrubby oaks as host plants. The adult butterflies of this species feed off of nectar from flowers of heaths including wild azalea and blueberry. They have also been known to feed on nectar from blackberry and dandelions.


The sleepy duskywing is univoltine throughout its range, even in the south, and this factor may limit its abundance. Its one flight occurs from January to May in Florida and Texas, and from March to June in the rest of its range. Overwintering occurs when the sleepy duskywing is a fully-grown caterpillar.


The sleepy duskywing is considered secure globally. The sleepy duskywing is a southern-based butterfly, and the numbers, breeding range, and emergence time of this species may be expected to increase in response to climate warming, if habitat is sufficient. The main threat to sleepy duskywing is loss or degradation of its scrub oak/pitch pine barrens habitat. For many reasons, this habitat is and should remain a conservation focus.

In 2015, the New Jersey Endangered and Nongame Advisory Committee recommended a Special Concern status for this species within the state, but no formal rule proposal has been filed to date.

Text written by Michael Colella in 2015.


  • Butterflies and Moths of North America
  • NatureServe
  • Butterflies of Massachusetts
Scientific Classification

Kingdom: Animalia
    Phylum: Arthropoda
       Class: Insecta
          Order: Lepidoptera
             Family: Hesperiidae
                Genus: Erynnis
                   Species: E. brizo

Find Related Info: Invertebrates, Special concern

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