Observation: Photinus pyralis
Primary Observer:
Carl Manthey
Event Date:
2025-06-21
Status:
Verified
Survey
Site Name:
Great Marsh, Elverson, PA
Province/State:
Pennsylvania
Event Date:
2025-06-21
Time of Day:
Night-Time
Start Time:
20:30
End Time:
22:00
Number of Observers:
4
Primary Observer:
Carl Manthey
Additional Observers:
Bernard Brown, Myrna Villanueva, Diana Cormack
target_species_genus:
unknown
target_species_species:
unknown
Location and Habitat
Location Accuracy (meters):
500-1000
Habitat Type:
Open Freshwater Wetland - Wetland Bog, fen, freshwater marsh
Habitat Type Notes:
Habitat is highly variable. Land was originally a large marsh. It was briefly drained and used as a dairy farm until the 1950s. At that time, it was allowed to revert to a marsh, although a number of ponds were built. The area viewed includes wet marsh with cattails, ponds with spatterdock, swamp with black willow, wet meadows with native perennials, mowed grassy paths, and higher ground with red maple, black cherry, spicebush, and oak. There are also a couple soybean fields and a sheep pasture.
Elevation (meters):
150 - 200
Area Searched (hectares):
7
Artificial Light Sources
Vehicles: No
Street Lights: No
Buildings: No
Street Lights: No
Buildings: No
Artificial Light Types
Sky Glow (diffuse illumination in the sky): No
Light Trespass (light cast on surfaces beyond its intended target): No
Glare (bright light causing visual discomfort): No
Light Trespass (light cast on surfaces beyond its intended target): No
Glare (bright light causing visual discomfort): No
Artificial Light Notes:
Observation
Observation Type:
With Flash Data
Number Observed:
50+
genus:
photinus
Species:
pyralis
Observation Notes:
Specimen Voucher Number:
Flash Behavior
First Flash Time:
20:40
Last Flash Time:
21:15
First Flash Temp (F):
78
Last Flash Temp (F):
78
Flashes in Pattern:
1
Flash Color:
Yellow
Flash Pattern Period:
slow
Flash Duration:
0.75 sec
Flash Interval:
5 sec
Male Height Zone:
Low (0-3 ft)
Flash Location:
Slow lazy flash rising starting 6 inches above the grass. Abundant over mowed grass, but much less common elsewhere.
Male Flash Behavior:
Caught at 8:40 flying low over mowed grass across the road for a sheep pasture. Slow lazy flash rising starting 6 inches above the grass. One flash per 6 seconds. Looks like rising spark from campfire. Abundant over mowed grass, but much less common elsewhere.
