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For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
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Jay Watson
Conservation Biologist

Frosted Elfin (Callophrys irus)



Frosted Elfin (Callophrys irus), listed as Threatened in Wisconsin, has been found in pine barrens, oak savanna, and edges of sandy oak/pine forest. Wild lupine (Lupinus perennis) is the larval host plant and grows on sandy soils under canopy in dry oak/pine forest where it may occur sparsely and in a vegetative state. Frosted elfins are most often found in habitat where the lupine is common to abundant and the patch size is very large (at least 2 to 2.5 acres). Adults are present from early May to mid June and usually fly for 21-30 days.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Frosted Elfin (Callophrys irus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Callophrys irus in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS1
Global RankG2G3
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was originally presented as part of the Online Field Guide to Rare Lepidoptera: Bogs and Barrens.

Identification: Adult males have uniform dark brown wings above with a long stigma; females are dark brown basally becoming orangish-brown toward the outer edge. The hindwings are tailed with the ground color below light brown marked with darker brown basally and medially. Areas of frosty gray scaling line the inner and outer margins of the hindwing below. The ventral hindwing must be closely examined to make an identification. The combination of tailed hindwings, lack of sharply contrasting basal and outer areas of the hindwing, and frosty gray scaling below are diagnostic. Wingspan: 25-30 mm, Length of forewing: 13-15 mm. Larvae are pale blue-green with several white lines down the back and one along each side with oblique white dashes in between (Layberry et al. 1998).

Similar Species: Henry's elfin (Callophrys henrici) is the only other Wisconsin elfin with tailed hindwings. They are orange-brown above and display a distinct contrast between the basal and outer areas of the hindwing below and the white edging between them. The hoary elfin (C. polios) often occurs in the same localities but lacks tailed hindwings.

Habitat: Pine barrens, oak savanna, and edges of sandy oak/pine forest. Wild lupine (Lupinus perennis) is the larval host plant and grows on sandy soils under canopy in dry oak/pine forest where it may occur sparsely and in a vegetative state. Most often, lupine patches occur on the edge of the woodland or in the open to semi-open jackpine/oak barrens habitat. Frosted elfins are most often found in habitat where the lupine is common to abundant and the patch size is very large (at least 2 to 2.5 acres). Lupine grows best in sandy soils and full sun where competition from shrubs and tall grasses is minimal. It spreads quickly in areas recently cleared by fire, logging, grazing, or other disturbance.

Nectar Source: Most nectaring has been observed on blueberry (Vaccinium spp.) (Nielsen 1999).

Host Plant: Wild lupine (Lupinus perennis) in Wisconsin. Other legumes including Baptisia spp.have been recorded in other parts of the range (Borkin, pers. comm.).

Associated Species: Persius duskywing (Erynnis persius), hoary elfin (Callophrys polios), Henry's elfin (C. henrici) and Karner blue (Lycaeides melissa samuelis).

State Distribution: Uncommon and localized throughout its range. Adams, Jackson, Juneau, Monroe and Wood counties.

Global Distribution: Occurs in local colonies from Maine west across New York and southern Michigan to central Wisconsin; south along Atlantic coast and Appalachians to northern Alabama and Georgia. Isolated colony in eastern Texas, northwest Louisiana, and southwest Arkansas.

Rationale for Species Listing and Threats: Habitat loss due to woody species and forest encroachment. Overwintering immatures are presumed exposed and vulnerable to being killed by fire. Larvae may be impacted by Bt spraying for gypsy moth control.

Phenology: Adults are present from early May to mid June and usually fly for 21-30 days.

Life and Natural History: Univoltine. Oviposition occurs on young stalks of flower buds. Larvae consume flowers and developing seed pods. They pupate in a loose cocoon at the base of the hostplant in the litter (Opler and Krizek 1984). Scott (1986) states that the pupae hibernate in the leaf litter silked together. A remnant-dependent species (Panzer et al. 1995).

Survey Guidelines: Frosted elfins are weak fliers (Pyle 1997). They often sip moisture from damp forest trails. New county records should be documented with good photos of the underside, but preferably with voucher specimens.

Inventory, Monitoring and Research Needs: Locate additional populations, particularly in sites managed with prescribed burning and monitor population levels over extended years.

Management Guidelines: Sites managed with prescribed burning should be divided into several burn units leaving refugia for the species. Mowing should be done before April 15 or after July 31 with a 4 inch blade height. See the Bureau of Endangered Resources Incidental Take Protocol for more specific information.



Frosted Elfin

Photo © Robert Borth.

Frosted Elfin

Photo © Robert Borth.

Frosted Elfin

The globally rare Frosted Elfin occupies pine and oak barrens remnants in which this butterfly's larval food plant, wild lupine, is common.

Photo © Mike Reese.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Frosted Elfin. Only natural communities for which Frosted Elfin is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Ecological landscape associations

The table below lists the ecological landscape association scores for Frosted Elfin. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Frosted Elfin occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, December 22, 2022