2018: The Butterfly Year in Review


Watching snow falling on the garden outside my kitchen window this morning, it appears I can finally call a wrap to this year’s butterfly season.  For weather, 2018 had it all in the mid-Atlantic states — very early season warm spells followed by intense cold snaps, a wet and rainy early summer with a hot, dry July and then monsoons in August and September.  The combination did not result in a very good year for most mid-Atlantic butterflies — nor did it give us much in the way of good weekend weather for field exploration! Below are some highlights.

Azures, Blues, and Coppers — There were some very early dates (late February) for the spring form of Summer Azure; a return to frigid winter put an end to this flight for a month and few emerged during their normal late-March and early-April timeframe.  The second brood was likewise small (apparently the eggs and caterpillars produced in that first early flight perished), but by the end of the summer this azure was back to almost normal abundance in the mid-Atlantic, and the last flight was a long one, with adults on the wing well into October.  The univoltine Spring Azure did not fare so well; it is increasingly harder to come by and 2018 proved no exception.  Silvery Blues did well in their limited range, but the flight was short.  Eastern Tailed-blues suffered greatly; first brood members were scarce, and it wasn’t until the late summer brood that anything approaching normal numbers appeared.  Appalachian Azures appeared late in small numbers but lingered well into mid-June.  Bronze Coppers appeared to have a good flight at midsummer (good at least for this dwindling species); American Coppers were not common but flew as late as Hallowe’en this year.

Elfins — This was a very good year for Henry’s Elfin, which bordered on abundant (for an elfin) in most of its range.  Eastern Pine Elfin numbers were down.  Even well known populations of Brown Elfin turned up few individuals; it emerged late and the emergence seemed staggered over several weeks.  Frosted Elfin flew in only modest numbers this year, and apparently not in all its usual locations.

Hairstreaks — In all, a poor year for hairstreaks, especially the first half of the summer.  The satyrid hairstreaks were quite uncommon, with surprisingly low numbers of Banded, Striped, and Coral Hairstreaks.  The first half of the season also lacked much in the way of Red-banded, White M, or Gray Hairstreaks, all of which however rebounded well in late summer.  Great Purple Hairstreak had a surprisingly good run in the areas around Blackwater NWR this year; many folks got their lifer sighting of this butterfly in 2018. Juniper Hairstreak also had an unusually good year, with a possible partial third brood late in the summer.

Swallowtails — This season was a middling one for swallowtails.  Eastern Tiger Swallowtail, usually one of our most abundant swallowtails, mustered a very poor first flight and never really recovered.  There were only sparse reports of Appalachian Tiger Swallowtail.  Both may have suffered early season mortality during cold snaps that occurred after a very warm, very early spring.  Zebra Swallowtails had mostly normal flights, including an apparent partial fourth brood in some parts of the area.  Spicebush and Pipevine Swallowtail numbers were down (except in downtown DC, where Pipevine is insulated from the vagaries of weather by surviving on exotic Aristolochia plants wintered over in greenhouses by the Smithsonian).  Black Swallowtail was MIA for the most part until late summer, when a normal brood emerged.   Too few Palamedes reports came in for comparison with previous years; apparently not many of our gang visited its haunts along the Pocomoke River swamps this year.

Whites and Sulphurs — It was generally a bad year for pierids.  The lone bright spot was the largest flight of Olympia Marbles in 15 years or more; one could find them at almost any likely spot in Green Ridge State Forest.  Marbles emerged late (middle of April) and flew late (well into May).  By contrast, Falcate Orangetip numbers were way down across the area, emerging quite late and finishing up early.  Even normally ubiquitous Small (Cabbage) Whites were a good find in spring and early summer; they were easier to tally as the summer wore on but still nothing like their normal abundance.  Both common sulphurs, Orange and Clouded, had terrible flights in spring and summer and only flew reasonably well in the last brood of the season.  Sleepy Orange didn’t make an appearance until mid-summer, and never reached the large numbers we sometimes see.  Cloudless Sulphurs required diligent searching all summer long, appearing only late in the season.  There was a single report of Little Yellow in the region that I’m aware of, and no Dainty Sulphur reports.

Metalmarks — Northern Metalmark had one of its best flights in the past few years.  Virtually every stem of woodland sunflower had its complement of metalmarks throughout the Green Ridge forest complex; the high numbers appeared to be repeated in VA and WV.

Anglewings and Cloaks — Reliably our first butterflies of the spring, we saw rather few Eastern Commas or Question Marks until early fall, which at least gives us some hopes that if winter conditions are favorable we might have a normal anglewing spring in 2019.  Ditto for Mourning Cloaks, only even more so — just a handful of early spring sightings and the same for the close of the summer.  Gray Comma apparently showed up in regular numbers along the Appalachian Spine.  We missed out on any errant local tortoiseshells this year although they seemed to fly well in PA.

Crescents and Checkerspots –– 2018 may be best remembered in checkerspot history as the year we started to get a handle on the Northern Crescent-cocyta group complex in MD, with good numbers for the May brood in all three western counties.  The situation is not as clear for later in the season, mostly because (I suspect) we weren’t looking (I didn’t get into the field nearly as often as I had hoped). Our normally abundant Pearl Crescent made a very poor showing all summer, with just a few locations racking up high numbers in the early autumn.  There were a couple of microbursts of Silvery Checkerspots in a few local irruptions; at least one explosion of caterpillars came to naught in the wet, moldy days of midsummer.  Very few reports of Baltimore Checkerspots were recorded this year.  By contrast, field work in Garrett Co. revealed some new populations of Harris’s Checkerspot which, while never common, flew reasonably well in 2018.

Admirals, Viceroy, Emperors and Ladies — Red-spotted Purple was the only member of this tribe to have a good season in 2018.  Huge populations in May and again in August.  The May-June brood also sported some White Admiral morphs.  No significant migrations of Red Admirals or American Ladies were noted; neither was abundant anywhere this season and in fact American Ladies were sparse until late summer.  Red Admirals could be found on most field trips from midsummer on, but not in any significant numbers.  Painted Ladies were at best uncommon, though sightings picked up in early autumn.  Viceroy was uncommon all season long.  Common Buckeye only lived up the “common” part of their moniker late in the season, and even then in only modest numbers.  Neither emperor — Tawny or Hackberry — mounted very good flights in 2018.

Snouts — Poor numbers all season.  Little if any migration noted.

Satyrids — A mixed report on satyrid brushfoots.  Whether for lack of field activity or because its numbers were down, there were hardly any reports of Carolina Satyr.  Little Wood Satyr flew well but not in very good numbers.  Northern Pearly-eye numbers seemed about on par with recent years; Appalachian Brown numbers bucked the trend and this species seemed to be doing quite quite well in 2018.  Common Wood Nymph also had a good year in terms of flight time; it showed well all summer long, if in rather low numbers.

Fritillaries — With the exception of Meadow Fritillary, frits were hard to come by this season.  Meadow Fritillaries flew early and late and in good numbers across a variety of habitats across the region.  The first brood of Great-spangled Fritillaries was almost non-existent; they gained some numbers and flew late into late summer but nothing like their normal abundance.  Not many reports of either Aphrodite or Atlantis Fritillaries from the western counties.  Diana Fritillary had an exceptionally poor year.  Silver-bordered Fritillary was represented by only a handful of reports.  Variegated Fritillary had modest flights in the early season, and even late in the summer was overall uncommon with a few scattered local irruptions.  Where they were abundant they were everywhere, but this was not a widespread phenomenon.  The Gulf Fritillary pop of 2017 was not repeated (IMHO, because there wasn’t a mass migration of eclipse-viewers transporting them up here).

Monarchs — Likely the best flight in a decade here in the mid-Atlantic.  We’ll see if we have similar numbers returning from overwintering in Mexico; for the mid-Atlantic it increasingly appears that whatever is putting downward pressure on Monarch populations has little or nothing to do with milkweed availability on the East Coast into maritime Canada.  Queens apparently made it this year to NJ and into the Midwest but not locally.

Spreadwinged Skippers — Most of the spreadwings had a decent year, beginning with Horace’s and Juvenal’s Duskywings in the early spring, as well as the Dreamy and Sleepy contingent.  There were a couple of early dates for Wild Indigo Duskywing — April! — and then it became hard to find until the very end of summer.  Horace’s had a terrific late-summer flight.  Silver-spotted Skipper flew in small numbers season-long; Hoary Edge numbers seemed down in its limited range.  The spreadwing skipper standout for 2018 was a couple of very early (late June-early July) teases by Long-tailed Skipper, which after a complete hiatus would become almost common in early autumn. Common Checkered-skipper was anything but; ditto for Common Sootywing and Hayhurst’s Scallopwing.  Northern Cloudywing was common in early spring; few cloudywings of any stripe were around later in the season,

Grass Skippers — a poor flight for almost all species, especially early in the year.  Few species showed up in early summer, save for modest numbers of Zabulon and Hobomok.  Zabulon had a short but intense mini-explosion in late summer.  Indian Skipper flew early and in low numbers.  Mulberry-wing numbers were stable in the one location for which we have a report.  European (Essex) Skippers showed in good but not spectacular numbers, as we sometimes see with this species.  With few exceptions, our normally common grass skippers — Sachem, Crossline, Little Glassywing, Tawny-edged, Dun, broken-dashes — failed to put in appearance early in the season, but flew in a brief series of intense activity in the August-September timeframe.  Fiery and Sachem approached their normal abundant status late in the season  Clouded and Dusted Skippers both had less-than-average numbers for the year.  Leonard’s Skipper had a shorter flight than usual, likely because extreme drought took out their nectar sources early.  Among the coastal and marsh skippers, only one good spike of activity in midsummer stood out; even then really only Aaron’s, Broad-winged, and Rare had what could be considered decent flights.  Dion and Delaware were difficult spots this year.  Pepper and Salt Skipper in MD seems to have taken a year off; reports from WV suggest it had an otherwise normal year.  Cobweb Skipper appears to have had an off year; very few reports.  The grass skipper highlight was Brazilian Skipper, which offered an unprecedented flight here in the mid-Atlantic.

Here’s hoping 2019 will be a better field year all-round.  That will take, among other things, better winter weather — and especially a moderate spring with no see-sawing between Arctic and tropical temperatures.  And at least a handful of summer weekends that aren’t soggy!  A lot of things will conspire to keep me out of the field next summer, but keep your eyes out for MD-LepsOdes ad hoc excursions on short notice by following the listserv at https://groups.google.com/forum/#!forum/mdlepsodes.



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2 Responses to 2018: The Butterfly Year in Review

  1. ravenfrank says:

    Hayhurst scallopwing had a good very local showing here on our property. 4th year running. I had no idea they were so colonial.

    As for Monarch numbers here in Pleasant Valley (SE Washington County, MD), they were EVERYWHERE in abundant numbers. Best flight in 12 years.

    Diana fritillary was at least sighted and recorded for Bath County, VA, albeit not on my NABA count day. Males and females.


  2. Fred Habegger says:

    I enjoy seeing your reports throughout the season. Thanks!

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