Photo: Eastern Tiger Swallowtail, Sheryl Pollock
Jim Waggener
0730, Sat., 28 Jun. 2025: Not the best of mornings for finding butterflies; sunless, oppressively humid, just the slightest of breezes, downright uncomfortable. But more than two dozen volunteers were ready for the challenge, forming small teams to cover Occoquan Bay NWR, and other promising sites nearby (Meadowood Recreation Area on Mason Neck, Occoquan Regional Park, the Metz Wetlands Preserve and Rippon Landing). Following a routine honed over decade of practice, every adult butterfly that could be identified would be recorded and, if unusual or rare, photographed. All done by sight, without capturing or harming any of the various swallowtails, sulphurs, skippers or other butterflies encountered.
This particular count was begun in 1990s to document the lepidoptera of a then U. S. Army facility slated for closure, both to draw public attention to the site’s unique nature and to generate support for its permanent protection. By the time the Occoquan Bay refuge was finally established in 1998 the count had taken on the form and routine that are followed today. Over the years, other sites with varied natural habitats were added. Certified in 2001 by the North American Butterfly Association, the Occoquan Bay-area Count presently encompasses the four sites (listed above) that are surveyed in a multi-year, citizen science project, long supported by the Northern Virginia Bird Alliance and other regional organizations.
Over the years, count results have varied considerably in numbers of species and individual butterflies. For example, 2005’s count resulted in 19 species and 114 individuals while 2013’s count resulted in 42 species and 1022 individuals. The count in 2015 resulted in 37 species and 1269 individuals, with the average over the past 24 years at 33.9 species and 593.6 individuals. Expectations for this year’s tally diminished as unfavorable conditions persisted until late morning. Less than an hour before count’s end, breaks appeared in the clouds, spurring heightened butterfly activity. While results from individual sites were not impressive, combined they were unexpectedly positive: 34 species and 828 individual butterflies.
In addition to the butterflies, this day’s count produced reports of a Mississippi Kite, confirmation of Blue Grosbeaks breeding, an uncommonly encountered Mole King Snake, other wildlife (Rough Greensnake, Box Turtle, Beaver, Cottontail, etc.) and plants (including first-of-season records of bloom).
In sum, another successful count and more records for the expanding base of data on these important natural sites. Certainly a tribute to the diversity and health of habitats across the various sites. A tribute as well to the skills and perseverance of the teams and leaders of today's count. A more difficult job than expected, perhaps, but exceptionally well done.
Learn more about butterfly counts and how you can join us!