As Tom Stock noted in an email to me today, for lepsters this year, April well may be the cruelest month. Here in the DC region we are expected to have record-breaking low temperatures over the weekend, coupled with strong winds, rain, snow and other precipitation that set up the ingredients for a repeat of seasons where late cold and wet weather depresses the entire rest of 2016.
So this week’s Forecast will be slim, since very few new butterflies have emerged during the course of the last few chill and blustery days. Eastern Tailed-blue is one such critter, and Eastern Tiger Swallowtails continue to trickle out here in the metro DC area.
Not far to our south, though, specifically around Charlottesville VA, a lot of new emergences were noted: Spicebush Swallowtail, Clouded and Orange Sulphurs, Variegated Fritillary, White M Hairstreak and Silver-spotted Skipper. I haven’t checked to see how far south this weekend’s polar vortex is scheduled to dip but I can’t imagine this will be salutary for these species.
Despite the low temperatures, Henry’s Elfins were still flying in the cold this week at Patuxent North in Anne Arundel Co MD, and azures were mostly hunkered down but occasionally in flight area-wide very close to the ground where thermal radiation raises the temperature. The elfin sightings (8 of them!) were Richard Orr’s; be sure to check out his superb photostream of natural history subjects while watching the snow come down tomorrow morning.
The cold temps and wet days do more than kill adult butterflies and delay emergence; the hard frosts the past couple of days have already killed sensitive new foliage around my neighborhood (where eggs and caterpillars could already be present), severely reducing breeding populations and subsequent broods of multivoltine summer leps like Zebra and Tiger Swallowtails. They could also prolong our several-years-long drought of good southern migrants this fall if the freeze line forges very far southward.
The Olympia Marble foray to Green Ridge State Forest that we moved up to this weekend because the species was at peak last week is being rescheduled back to its original weekend April 16 or 17; I’ll make that call closer to the date depending on the weather but preference is for Sunday the 17th. Check the LepLog calendar for updates and information.
If by some miracle you have butterfly sightings to share from the field this weekend, post or send them for the next Weekend Forecast. In the meantime, visit us at https://leplog.wordpress.com/ and on Google Groups at MDLepsOdes.