Oak Hairstreak

Satyrium favonius

Summary 4

The Oak Hairstreak or Southern Hairstreak (Satyrium favonius) is a butterfly of the Lycaenidae family. It is found from southern New England and the Atlantic Coast south to peninsular Florida and west to central Illinois, south-eastern Colorado and the Gulf Coast.

Description 5

Very small—size of thumbnail. Almost never seen with wings open. Two tails on each hind wing. Below: forewing and hind wing gray-brown with narrow, black-and-white postmedian bands that on hind wing form an "M" near the tails. Orange spot near tails touches the margin but not the "M" mark. In peninsular Florida and along the south Atlantic coast, the hind wing has longer tails and more extensive orange and blue markings on the underside.

Similar Species 5

White M Hairstreak is grayer below, has a small white dot near leading edge of hind wing (usually missing in Oak), has a larger orange spot that touches the "M" but not the margin, and is brilliant blue above (visible in flight). Gray Hairstreak is gray below (but may appear brown when heavily worn), the postmedian bands include orange, the orange spot at hind wing tails is larger, and usually has a thin black line across the inner side.

Larval Host Plants 5

Oaks (Quercus spp.) in the White Oak group (Fagaceae).

GTM Occurrence 5

The Oak Hairstreak is considered an uncommon species at the GTM. It occurs along all Transects but is equally found along the Marsh Pond Overlook (Transect B) and the Red Bay Walk (Transect D). This is a spring species being found during April and May. It has only been observed in 2009 and 2010. There have been 10 specimens observed as of December 28, 2015.

Distribution 6

Global Range: Eastern Massachusetts down the Atlantic Coast and Piedmont to southern Florida, west to central Illinois, Kansas, Oklahoma and eastern Texas, and disjunctly northeastern New Mexico and adjacent southeastern Colorado; but absent from most of Pennsylvania, most of Ohio and the Appalachians. While the Type specimen for the widespread subspecies S. f. ontario might have really come from Ontario, there have been no know specimens or photographs from Canada in over 120 years. See Layberry et al. (1998). Subspecies S. f. favonius is mostly Floridian but occurs up the immediate coast of Georgia and belnds into the continental form.

Habitat 7

Comments: For subspecies S. f. favonius; wooded coastal areas, barrier islands, oak hammocks. For the most widespread subspecies S. f. ontario: a variety of dry oak dominated forest and woodland situations including sometimes barrens. Probably far more general than realized as adults apparently are mostly in the canopy. For subspecies S. f. autolycus: a variety of woods, oak brush and edges (Opler, 1999).

Nature serve conservation status 8

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: With S. f. ontario included as a subspecies, this hairstreak is widespread in the eastern and central USA except along the northern border and in the mountains. It is probably much less rare than supposed because it apparently stays mostly high in the oaks, but until this is better documented there will be some doubt as to its real status. It does not appear to be declining and apparently expanded its range in the northeast in the 1970s and 1980s. Habitats are usually rather ordinary oak forest or woodlands, although also there are occurrences on some inland barrens.

Sources and Credits

  1. (c) Gerald Carter, some rights reserved (CC BY-NC-ND), http://www.flickr.com/photos/47573424@N00/137729800
  2. (c) Richard Crook, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/richardwc/5577193033/
  3. (c) Bob Peterson, some rights reserved (CC BY-SA), http://www.flickr.com/photos/pondapple/4606930327/
  4. Adapted by GTMResearchReserve from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Satyrium_favonius
  5. (c) GTMResearchReserve, some rights reserved (CC BY-SA)
  6. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28759568
  7. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28759573
  8. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28759565

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Category name uncommon
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