Hairstreak Surprise in Hudson—A First for NH!

[George DeWolf]

Today I visited the powerline clearing off Musquash Road in Hudson (click here for Google Map directions) with Steve and Jane Mirick and Laurie Shepard. This powerline corridor extends into Massachusetts, where Tom Murray photographed a Hoary Edge in Groton, roughly eight miles from the New Hampshire border, on June 23, 2023 (to see observation click here).

Mike Thomas and I had surveyed this site on Saturday and came up empty in our search for the Hoary Edge, but we took note of the abundance of Scrub Oak and thought the habitat looked promising for Edwards' Hairstreak and perhaps even the Northern Oak Hairstreak, a species not yet documented in New Hampshire.

After walking about 0.85 miles into the powerline clearing, we came upon a patch of New Jersey Tea in bloom atop one of the higher knolls. Steve immediately trained his camera on a hairstreak and quickly became excited, asking if I had brought a field guide. I pulled the Swift Guide from my pack, and we frantically flipped back and forth between the Gray Hairstreak and Northern Oak Hairstreak pages while comparing the field marks to the image displayed in his camera's viewfinder. 

The excitement mounted as so many characteristics pointed toward Northern Oak Hairstreak: the brown ground color, the small white basal spot on the hindwing, the orange cap above the blue spot, and the white-and-black postmedian band on the hindwing ending in a sharply pronounced "M." All of these features strongly supported Northern Oak Hairstreak and ruled out Gray Hairstreak. Later, when considering the White M Hairstreak as another possibility, I noted that we appear to be between broods for that species, and the White M lacks the black-centered orange spot found in Northern Oak and Gray Hairstreaks.

It seems difficult to challenge the conclusion that this represents the first documented observation of Northern Oak Hairstreak in New Hampshire (to see observation, click here).

There are many reasons to explore this corridor beyond the possibility of finding a rare butterfly. If you've never visited, it is a botanically interesting site. In addition to the the many instances of Scrub Oak and New Jersey Tea, we found Canada Toadflax, Smooth Carrionflower, Poke Milkweed, Common Milkweed, Clasping Venus' Looking Glass—a beautiful flower and a first-time find for me—and Northern Bush Honeysuckle.

Although we did not encounter any tick-trefoils, the preferred larval food plants of the Hoary Edge, we did find Round-headed Bush Clover and Eastern Wild Indigo, both of which are known to occasionally serve as host plants for Hoary Edge caterpillars.

We also found numerous hickory saplings, which I believe were Pignut Hickory (Carya glabra). The Hickory Hairstreak, which has been documented just across the border in both Massachusetts and Vermont, but has yet to be recorded on iNaturalist in New Hampshire, could be a possibility here in July.

Perhaps the fact that I made the hour-and-forty-minute drive from Wentworth twice in four days is testament enough to how highly I regard this site.

Here's Steve's tally of the butterflies we observed:

Silver-spotted Skipper – 6
Hobomok Skipper – 1
Azure – 1
Banded Hairstreak – 1
Northern Oak Hairstreak – 1
Monarch – 1
Great Spangled Fritillary – 6
Viceroy – 1
American Lady – 2
Little Wood-Satyr – 2
Eastern Tiger Swallowtail complex – 2
Clouded Sulphur – 1
Cabbage White – 2

It was a great day spending time with Steve, Jane, and Laurie. I saw far more than I would have on my own thanks to their extra sets of eyes. As is always the case when I'm with Steve, I found myself drawn even deeper into the world of robber flies and tiger beetles. We had the opportunity to observe New Hampshire's largest robber fly, the impressive bee mimic Laphria grossa, and Asilus sericeus, the notorius Butterflyhunter.

George

[George DeWolf]

Correction. I wrote most of this last night expecting to post it then, so we actually visited the site “yesterday.”

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[George DeWolf]

Just one more observation about the Musquash Road powerline clearing in Hudson (click here for Google Map directions): another reason to visit is the possibility of spotting a Juniper Hairstreak. This two-brooded butterfly has been recorded only once in New Hampshire on iNaturalist, but it may well occur here from mid-May through July, given the presence of Eastern Red Cedar (Juniperus virginiana) along the clearing.

Although Common Juniper (Juniperus communis) is abundant in this habitat, I have not been able to verify that it serves as a larval host plant for the Juniper Hairstreak.

George

[Zack Weber]

Thanks for the report.  I went to check it out from 1230pm - 400pm today.  Conditions were mostly bright sun and little wind.  Didn't find the Oak Hairstreak or Hoary Edge.  There was a single Gray Hairstreak perching on oak leaves near your Oak Hairstreak coordinates which got my heart racing.  However it was very fresh and I could see multiple field marks quite clearly that ruled out Oak.  I explored the oaks that are located a ways beyond your hairstreak GPS coordinates, but spent the largest amount of time near your coordinates.  Sightings, which were a bit fewer than expected / hoped for given the good weather conditions:

Silver-spotted Skipper - 2

Common Ringlet - 5? (flybys, so not positive on all IDs)

Great Spangled Fritillary - 2? (flybys, so not positive on IDs)

Mourning Cloak - 1

Eastern Tailed-Blue - 2

Gray Hairstreak - 1

Sulphur sp - 1 (guessing Clouded, but couldn't rule out Orange during flyby)

Cabbage White - 1? (flyby, so couldn't rule out whitish Clouded Sulphur)

Despite being during the heat of the early afternoon, I enjoyed a surprising amount and variety of bird songs and sightings.  There were also a number of dragonflies and tiger beetles like you pointed out, including a lifer subspecies for me.

Zack

[George DeWolf]

Very pleased you got out there, Zack—and not a bad tally, given that numbers appear to be down this year on the heels of last year’s inclement spring weather. This clearing certainly has the potential to produce some special observations. Sooner or later the Northern Oak Hairstreak is sure to emerge again.

George

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