April ended on a blustery, gale-ridden note, and the first week of May looks to be unsettled and mostly wet. But for those who watch the fortunes of butterflies in the field, this rain is only an inconvenience to us but of critical importance to butterflies. Too much — especially combined with cool or cold weather — is generally bad for caterpillars, and particularly for those that feed or shelter at ground level in grass clumps or debris at the base of food plants. Adults can be knocked back a little too, but they’re more resilient and go into almost a refrigerated torpor to wait out the wet. But too little rain — and we’ve had rather a dry spell here in the mid-Atlantic — and nectar production is down, moisture to free ions for males is scarce and puddling opportunities rare, and eggs and young larvae are subject to dessication. So count your blessings for sunshine today and tomorrow and expect the rains to bring new species for Mother’s Day weekend.
But for now there hasn’t been a lot to report from the field over past week. Virginia iNaturalists reported 41 species on the wing (well, 39 if you discount the report of California Tortoiseshell that iNat ID’s from a poor photo of a Pearl Crescent; and the Common Buckeye photographed on a madly blooming lantana with an Ocola Skipper on a nearby flower — clearly fudged on the date). The tally did include last week’s prognosticated Red-spotted Purples, and additional Cloudless Sulphurs (which appear to be on track, weather permitting, for an early season in the mid-Atlantic).
Maryland racked up 37 species, including the first regional report of Harvester for the season from Green Ridge State Forest. Other notables included Cobweb Skipper (multiples of those were also reported from Green Ridge this past week, and singletons elsewhere), and White M Hairstreak.
Pennsylvania’s 26 iNat observations included a Blue Morpho from what looks like a painting or piece of fabric, so let’s call this 25. Meadow Fritillaries were part of the observations, as was West Virginia White.
Hairstreaks, blues, and elfins in general were an interesting group this week. The first solid reports of Red-banded Hairstreaks in any numbers were registered, but it appears this first flight will be a late, extended one or on the small side. Ditto for Gray Hairstreak, which is likewise being reported across the region but in very small numbers. Harry Pavulaan has commented on the local listservs about the poor showing of azures generally this season, although early Appalachian Azures were noted in Shenandoah NP. More Great Purple Hairstreaks were recorded this week as well.
In addition to the Cobweb Skippers noted earlier, Horace’s Duskywings have begun to tick up, joining the Wild Indigo Duskywings and Juvenal’s Duskwings already in numbers across the region, and Sleepy and Dreamy Duskywings in the mountains.
Among the late-flying spring univoltine species for which a few reports still straggled in are Falcate Orangetips and Olympia Marbles; see them now or wait until next year!
A dynamic ruderal duo: Not to be picking collegiate sides, but meadows in the mid-Atlantic are sporting lots of Gator colors this week, with good flights of Eastern Tailed-blues (blue) and Pearl Crescents (orange). Both are typical of what we know as ruderal (from the Latin ruderalis, rubble) habitats: weedy, often disturbed habitats in full sun, where the host plants clover (for the ETBs) and field asters (for the crescents) abound. This habitat preference will be a good clue for those of us out hunting the “other” crescent — notionally Northern Crescents of the cocyta-group, which favor damp streamsides, palustrine meadows, and shady woods margins bordering grassland. Once the habitat starts to succeed into shrubs and trees, ruderal species decline and finally wink out. Other ruderal specialists include Checkered Whites, American Copper (good numbers reported this week), Sachem (reported again this week), and Common Checkered-skipper (good numbers for this one also noted this week).
Prognostications: The next week or two should yield for us Common Sootywing and Common Roadside-skippers, as well as the first Zabulon and Hobomok Skippers of the season. Look for Giant Swallowtail to round out the list of expected swallowtail species, and for the first of the Appalachian Swallowtails (which in Maryland at least often fly in the relative lull between flights of Eastern Tiger Swallowtail).
Share your observations and questions about regional butterflies here as a comment or, if you’re in Maryland or DC, on MDLepsOdes, the Google Group for field observations of leps and odonates.