We had a really good turnout Saturday (July 12) for the annual summer butterfly count at Green Ridge State Forest in Allegany Co. Maryland.
We had perfect butterflying weather this year, with fog in the morning that burned off quickly as we entered the field for our respective sectors at 9:30 from our meet-up point at Oak Barrel Cafe. Nectar along the GRSF roadsides was the best we have seen it in years, given recent abundant rain and the fact that it has not yet been mown this year so all the nectar was in good shape. Principal nectar plants were woodland sunflower, various mountain mints, spotted knapweed, and crown vetch. Notably absent this year from most of the forest was common milkweed, which requires disturbed areas to grow and the roadsides have not been recently graded to give it a chance to compete. Dogbane was past bloom.
This count originally was established to monitor the population of Northern Metalmarks, which occurs here in one of the largest (if not THE largest) in the U.S. We have historically had more than 200 metalmarks on this count, but this year numbers were off in 2025 a (still very respectable) total of 69. One hypothesis for the lower-than-normal number is last year's drought, which hit the nectar in GRSF (and particularly their favored woodland sunflower) especially hard, and probably led to lower fecundity and fewer successful young. Extended wet periods during larval development and pupation also lead to increased mortality (the caterpillars/pupae mildew or otherwise expire).
We had high numbers for the expected summer grass and roadside species, Eastern Tailed-blue (78, the most numerous butterfly on the count), Pearl Crescent (58), and Sachem (47). Dun Skipper (30) was the most abundant of the small dark skippers, but there were also Little Glassywings (14), Crossline (10), and Northern Broken-dash (5).
Nice surprises included Sleepy Orange (1), Common Roadside-skipper (1), Delaware Skipper (3), Snout (3) and Clouded Skipper (4). Notable misses were Harvester, Giant Swallowtail, either of the Ladies, and either of the Emperors.
Final Tally,
GRSF Summer Count 2025
Pipevine
Swallowtail 16
Zebra
Swallowtail 1
Black
Swallowtail 1
Eastern Tiger
Swallowtail 10
Spicebush
Swallowtail 12
Cabbage White 22
Orange Sulphur 3
Sleepy Orange 1
Banded
Hairstreak 2
Gray Hairstreak 3
Red-banded
Hairstreak 2
Eastern
Tailed-blue 78
Summer Azure 2
Northern
Metalmark 74
American Snout 3
Great Spangled
Fritillary 11
Pearl Crescent 58
Mourning Cloak 1
Red Admiral 4
Red-spotted
Purple 23
Northern
Pearly-eye 5
Little Wood
Satyr 14
Common Wood
Nymph 10
Monarch 3
Silver-spotted
Skipper 20
Horace’s
Duskywing 3
Wild Indigo
Duskywing 3
Least Skipper 2
Peck’s Skipper 1
Crossline Skipper 10
Northern
Broken-dash 5
Little
Glassywing 14
Sachem 47
Common
Roadside-skipper 1
Clouded Skipper 4
Delaware
Skipper 3
Unidentified
Swallowtails 1
Unidentified
Small Dark Skippers 7
Unidentified
Duskywings 1
TOTAL SPECIES 36
TOTAL
INDIVIDUALS 555
