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New Jersey Endangered and Threatened Species Field Guide

Image of Hickory hairstreak.Zoom+ Hickory hairstreak. Photo courtesy of Wade Wander.

Hickory hairstreak

Satyrium caryaevorus

Species Group: Invertebrate

Conservation Status

State: Special Concern



The hickory hairstreak is a relatively small butterfly with a wingspan of approximately 1 to 1 ½ inches. It is rarely seen with its wings open and is identified by the markings on the underside of its wings. The forewing and hindwing are grayish brown with dark postmedian “dashes” outlined in white which widen as they approach the outside of the forewing. On the hindwing, there is a pale blue patch that extends inward further than the adjacent orange and black spots. There is one tail on the hindwing on each side.

Its appearance is very similar to that of the banded hairstreak and identifiable differences are not consistent. In the banded hairstreak, the postmedian dashes are usually only edged on one side with white. The band on the forewing does not widen as it does on the hickory hairstreak.

The larvae of a hickory hairstreak are yellow-green and slug-like and are often striped lengthwise with white-green markings.

Image of Range of the hickory hairstreak in New Jersey.Zoom+ Range of the hickory hairstreak in New Jersey.


The hickory hairstreak can be found from southern New England west to Iowa and Minnesota and south to eastern Tennessee along the Appalachians. In New Jersey, it is primary found in the northern half of the state, with the southernmost report coming from Monmouth County.

Its habitat consists of deciduous and second growth forests and adjacent fields. The forests in its habitat almost always consist of hickory trees.


The primary food of hickory hairstreak larvae is leaves of hickory trees (Carya spp.). Other possible host trees include oak (Quercus spp.), ash (Fraxinus spp.), and chestnut (Castanea spp.), but it is though that these are often falsely reported.

Adult hickory hairstreaks feed on the nectar of a variety of flowering plants including common milkweed (Asclepias syriaca), staghorn sumac (Rhus typhina), New Jersey tea (Ceanothus americanus), white sweet clover (Melilotus albus), and dogbane (Apocynum spp.).


The female lays eggs in the twig end of a host tree in mid to late summer. The eggs overwinter without hatching. Larvae emerge and feed on the underside of leaves as they develop. They form a brown mottled chrysalis and most likely pupate in crevices in bark or in leaf litter beneath the host tree. They emerge as adults and have a flight period that lasts from mid-June to early August.


The hickory hairstreak is recommended for listing as a “special concern” species in New Jersey. This means that the species is especially vulnerable to habitat destruction or modification. As it has a specific host tree, any practice that has a negative impact on hickories would most likely harm the numbers of hickory hairstreaks. It is considered an uncommon to rare species that can go years without being reported in parts of its range. Its close resemblance to the banded hairstreak makes it the most widely misidentified hairstreak butterfly. A lack of confirmed reports means there is little known about its current status throughout its range and its conservation needs.

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 Kathleen Wadiak in 2015.


  • Butterflies and Moths of North America
  • Massachusetts Audubon Society
  • North American Butterfly Association, Massachusetts Chapter
  • North American Butterfly Association, New Jersey Chapter
Scientific Classification

Kingdom: Animalia
    Phylum: Arthropoda
       Class: Insecta
          Order: Lepidoptera
             Family: Lycaenidae
                Genus: Satyrium
                   Species: S. caryaevorus

Find Related Info: Invertebrates, Special concern

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