Share | facebook twitter instagram flickr flickr

Did you know?

Ospreys are an indicator species. The health of their population has implications for the health our coastal ecosystems.

Image of Instagram logo


New Jersey Endangered and Threatened Species Field Guide

Image of Hessel's hairstreak.Zoom+ Hessel's hairstreak. © Eric C. Reuter

Hessel's hairstreak

Callophrys hesseli

Species Group: Invertebrate

Conservation Status

State: Special Concern



The Hessel’s hairstreak is a tailed butterfly with wingspan on 2.5-2.8 cm. They are reddish brown with a mint-green overlay. Their white spots are surrounded by patches of red-brown and their forewing’s white spot is offset of the other spots. Commonly misidentified as the juniper hairstreak, they are distinguishable by that front most white spot and the Hessel’s has an overall more frosted appearance. The larvae are a bluish-green with dorsal and lateral white bars on each segment.

Image of Range of the Hessel's hairstreak in New Jersey.Zoom+ Range of the Hessel's hairstreak in New Jersey.


This species’ range is scattered along the Atlantic coast from southern Maine to the Florida panhandle. The greatest density of Hessel’s hairstreaks is found in New Jersey. They exclusively inhabit Atlantic white cedar swamps and bogs. Typically found within 30 miles of the coast, the Pine Barrens and Delaware Bay area are two of the most frequent occurrences of this species. They are absent from inland isolated cedar swamps in places like northern New Jersey, preferring the southern portion of the state. Hessel’s hairstreaks do not often stray from cedar swamps and may only do so to feed on nearby flowers.


Adult Hessel’s hairstreaks prefer flower nectar. In New Jersey, they are most often found at the blossoms of box sandmyrtle and black chokeberry. In other portions of their range, they will feed on a variety of flower blossoms. Flight seasons of Hessel’s hairstreak nicely coincides with the blooming of many flower and tree species. The larvae or caterpillars are restricted to Atlantic white cedar new growth and old foliage.


Males of this species perch on the tops of Atlantic white cedars to seek females during the beginning of May. After mating, females lay their eggs on branch tips. The egg stage is brief and larvae occur almost immediately for 4-6 weeks. The pupae diapause from July to the following May under loose bark. Adults are most frequently observed while feeding in morning or late afternoon. On particularly hot days, they can be observed through all periods of the day.


In New Jersey, the Hessel’s hairstreak is listed as species of Special Concern. They are not listed on a federal level. This species is considered rare throughout most of its range, however they are not imperiled. They do occur frequently in New Jersey, especially in the Pine Barrens.

This species has several threats facing them in New Jersey. The combination of clear-cutting, wildfires, and rising deer populations do not bode well for this species. Atlantic white cedars are commonly destroyed by wildfires, but are not able to readily regenerate themselves because of high deer populations. The deer quickly destroy any young saplings and in effect are severely limiting the Hessel’s habitat. The management of deer populations and establishment of new growth Atlantic white cedars are equally important in protecting Hessel’s hairstreak populations.

In the Delaware Bay area, sea level rise is a serious threat to Atlantic white cedars. They have little tolerance for salt water intrusion. The Delaware Bay area is losing a good portion of their white cedar and Hessel’s hairstreak habitat.


The Endangered and Nongame Species Program would like for individuals to report their sightings of Hessel's hairstreaks. Record the date, time, location, and condition of the animal and submit the information by submitting a Sighting Report Form. The information will be entered into the state’s natural heritage program, commonly referred to as Biotics. Biologists map the sighting and the resulting maps “allow state, county, municipal, and private agencies to identify important wildlife habitats and protect them in a variety of ways. This information is used to regulate land-use within the state and assists in preserving endangered and threatened species habitat remaining in New Jersey.”

Text written by Emily Heiser in 2011.

Scientific Classification

Kingdom: Animalia
    Phylum: Arthropoda
       Class: Insecta
          Order: Lepidoptera
             Family: Lycaenidae
                Genus: Callophrys
                   Species: C. hesseli

Find Related Info: Invertebrates, Special concern

Report a sighting

Image of Red knot.

Report a sighting of a banded shorebird or rare species.


Become a Member

Join Conserve Wildlife Foundation today and help us protect rare and imperiled wildlife for the future.


Wildlife Photographers

Join our Endangered Wildlife of New Jersey group on

Image of Flickr logo


Download the complete list of New Jersey's Endangered, Threatened, & Special Concern species.