North American Range
Elusive, little studied and sometimes misidentified, this hairstreak is uncommon in Vermont. Males perch high in trees to wait for females, sometimes engaging in lengthy battles with rival males. Both sexes descend to nectar in the morning and evening, affording opportunities for observation. They overwinter in eggs. Caterpillars feed on the lower surface of hostplant leaves.
Can be extremely difficult to separate from Banded Hairstreak. Some only identified with certainty by dissection of male genitalia. There is a pair of prominent spines projecting inward from the vinculum, which is absent in Banded.
Wing characteristics cited in field guides not reliable for some specimens, but very good for others. They include:
- Underwing postmedian bands are double with dark center in Hickory and usually single in Banded (if double, usually narrower).
- Thecla spot is an orange crescent relatively narrow in Hickory and not thicker than the black spot beneath it, while in Banded Hairstreak usually it is.
- Male scent pads are relatively slender in Hickory, about half the width of the discal cell. More than half the width of the discal cell in Banded.
- Both Hickory and Banded distinguished from Striped Hairstreak by the absence of an orange cap on the prominent blue spot at the lower corner of the underwing.
- Blue anal spot extends beyond marginal spots and paler blue.
One brood flying from end of June to end of August. Extreme dates: 30 June 1991 in Grand Isle (S. Griggs), 30 June 2005 in Arlington (K. Hemeon), 4 August 2006 in Manchester (M. Pfeiffer), and 20 August 1984 in Shelburne (J.R. Grehan).
Distribution and Habitat
Seldom recorded during VBS and only found west of the Green Mountains except for southern Vermont. They favor mixed deciduous forests and are most commonly found around forest edges, although this may be due to observer bias. Caterpillar hostplants are mostly hickory (Carya), but also ash (Fraxinus), and oak (Quercus) trees. Adults appear to be flexible in their choice of nectar source, including milkweed (Asclepias) dogbane (Apocynum), White Clover (Trifolium repens) and New Jersey Tea (Ceanothus americanus).