Butterfly Diary

For those of you headed into the field this weekend, these notes may be of interest in locating species of interest:

July marks the transition from summer nectar sources to the early fall bloomers. Already some of the early species of goldenrod are beginning to flower, and blossom heads are expanding on ironweed and Joe-pye weed, as well as on the many other boneset species. In the garden, mints and mint relatives like oregano and thyme are powerfully attractive to hairstreaks and sulphurs. Late summer butterfly magnets like butterfly bush, sedum, lantana and zinnias will soon be visited by clouds of grass skippers - but not just yet.

Milkweed and dogbane are fading on the Eastern Shore and Piedmont; butterfly weed also fading west of the mountains. Where early mowing cut down the initial growth there may be a good bloom still (or even a second bloom). In the mountains, there is still good milkweed, and spotted knapweed and other late summer roadside flowers are hitting their stride. Knapweed in particular is a magnet for Northern Metalmark along Allegany Co. back roads.

Pickerel weed is at peak along the margins of many local ponds and lakes, and attracts numbers of skippers, especially Broad-winged. In coastal locations, check pickerel weed also for less-common skippers like Salt Marsh, Rare, Delaware, and Dion.

The summer bloom of buttonbush is finished at Eastern Neck NWR (where liatris is coming on and pulling in skippers, and Joe-pye and ironweed should begin blooming this weekend or next - there's plenty of nectar there). July 4 butterflies in the garden at Eastern Neck included American Snout, many Black Swallowtails, Viceroy, Coral and Gray Hairstreaks, and a few freshly emerged Red Admirals (also scarce earlier in the summer).

Look for Giant Swallowtail along the Potomac, where it uses the larval host Ptelea trifoliata (wafer ash or common hop-tree), which is also in the Rutaceae along with the swallowtail's usual hosts of citrus and common prickly-ash.

Check out flowers under and around Eastern Red-cedar for Olive (Juniper) Hairstreak, fresh into its second brood and reported from southeastern PA this week. Banded Hairstreak may be experiencing an extended emergence, with photos of a very fresh specimen coming in this week from central MD. Older specimens were about at Ft. Indiantown Gap PA last weekend. Devil's walking stick (Aralia spinosa) is coming into bloom, and should be checked wherever it occurs for hairstreaks.

Roadside partridge pea and other senna-type plants could host ovipositing Cloudless Sulphurs (which are now beginning to show up in numbers as far north as Massachusetts) and Little Yellow (which has unaccountably not yet been reported in the region this year). Sleepy Orange was regularly seen in its first brood earlier in the year and should be emerging now in a second flight using the same hosts.

Wild Indigo Duskywings are in flight now, especially near patches of Pennsylvania crown vetch, which it has adopted as a larval host in addition to its Baptisia namesake. Horace's Duskywing is also out , so be sure to check for the cell-end white spot on the DFW. Cloudywings (Northern and Southern can be expected almost anywhere, much more rarely Confused) are flying now too and may be mistaken for duskywings; both are quite fond of red clover. You might confuse the newly emerged second brood of Common Sootywing for a duskywing or cloudywing at first glance; they're having a good second flight. Sachem is back in a new brood and should be commonplace within the next week, then faded into masquerading for less-common skippers by month's end.

Article by Rick Borchelt, Washington Area Butterfly Club

Nature Notes for 7/28/2013