Plants and Animals

Fixsenia favonius ontario Northern hairstreak

Key Characteristics

A small butterfly with a wingspan 1.1-1.5 inches (2.8-3.8 cm). Wing contains a tail. The upperside of the species is variable with varying amounts of orange in different individuals. Populations are mostly brown with little orange on the upperside. The underside is brownish gray, the blue tailspot has a narrow orange cap, and there is a white-edged black postmedian line with a "W" at the inner margin. The caterpillar is pale green with dark green median strop and lateral oblique green stripes.

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5T4
State Rank: S1 - Critically imperiled


CountyNumber of OccurrencesYear Last Observed
Lenawee 1 1975
Wayne 1 2008

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Edges of forests, along open trails, or glades. Open woods, forest edges, and roadsides. Larvae feed on foliage of oaks (Quercus spp.) and hawthorns (Crataegus sp.). Adults take nectar from wild plum and various early spring flowers, including white sweet clover, dogbanes, New Jersey tea (Ceanothus americana), and milkweeds.

Specific Habitat Needs

Along edges needed in: Dry southern forestDry-mesic southern forestMesic southern forest.

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Little is known about the northern hairstreak's status and distribution in Michigan. Threats to this species include habitat loss, degradation and fragmentation due to conversion to agricultural lands; altered fire regime; industrial, residential and/or recreational development; and encroachment by invasive species. Additional threats to this species include the use of pesticides and herbicides, incompatible natural resource management and lack of scientific knowledge about the species. Surveys are needed to assess the presence of this species in the state, and if present, its status, abundance and distribution. Research to obtain more information about this species' life history and ecology and efforts to assess severity of known threats and identify additional threats to this species in Michigan also are warranted. If the species is still present in the state, protection of the occupied site(s) in terms of both the habitat and the hairstreaks themselves is critical. Adequate suitable habitat at known extant sites should be maintained including sufficient densities of the species' host plants. Maintenance and long-term preservation of the habitats with which this species is associated will include protection and/or restoration of natural disturbance regimes or other natural ecological processes that drive the persistence and establishment of these natural communities.

Active Period

Flight from first week of June to fourth week of June

Survey Methods

In Michigan, this species is known from a single specimen captured in Lenawee County in late June nectaring on sweet clover. Adult nectar sources and larval host plants should be checked during visual surveys.

Visual, aerial net

Survey Period: From first week of June to fourth week of June

Time of Day: Daytime


Survey References

  • Klots, A.B. 1951. Peterson Field Guides: Eastern Butterflies. Houghton Mifflin Company, Boston. 349pp.
  • Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.

Technical References

  • Bouseman, J.K. and J.G. Sternburg. 2001. Field Guide to Butterflies of Illinois. Illinois Natural History Survey, Champaign. 264pp.
  • Cohen, J.G. 2001. Natural community abstract for oak barrens. Michigan Natural Features Inventory, Lansing, MI. 8 pp.
  • Cohen, J.G. 2004. Natural community abstract for mesic southern forest. Michigan Natural Features Inventory, Lansing, MI. 12 pp.
  • Glassberg, J. 1999. Butterflies through Binoculars: The East. Oxford University Press, New York. 242pp.
  • Klots, A.B. 1951. Peterson Field Guides: Eastern Butterflies. Houghton Mifflin Company, Boston. 349pp.
  • Nielsen, M.C. 1999. Michigan butterflies and skippers: A field guide and reference. Michigan State University Extension Bulletin E-2675, East Lansing. 248pp.
  • Stehr, F. W. 1997. Michigan Lepidoptera Survey Sites and Seasonal Occurrence of Michigan's Listed Species Annual Report 1997. 30 pp.+ MI Lepidoptera Survey Data Collection Form