Overview of Come critter spotting with us on a cold winter's night
This Shortwave (NPR) episode follows hosts Emily Kwong and Burleigh McCoy on a guided night hike in Patuxent River State Park, Maryland. Led by local naturalists, the group uses UV lights, a mercury‑vapor moth sheet, and close observation to explore what’s active or visually surprising in a winter forest — from fluorescent lichens to salamanders and (a non‑glowing) honey mushroom. The piece mixes natural history, field tricks, and invitations to get involved with community science.
Key observations and discoveries
- Lichen fluorescence: Under UV light, patches of lichen on tree bark shifted from dull gray/green to bright, neon colors (notably yellow and orange). The glow is caused by compounds in the lichen that fluoresce under ultraviolet light.
- Moths at a light sheet: A large white sheet lit with mercury‑vapor lamps attracted many moths, demonstrating how nocturnal insects are drawn to artificial light.
- Owl calling: Naturalists used owl calls (mnemonic: “Who cooks for you? Who cooks for you all.”) to try to elicit territorial responses from barred owls (no response that night).
- Fungi: The group found a jelly (snow) fungus and many other mushrooms. They discussed Schizophyllum commune (split‑gill), notable for having tens of thousands of mating types.
- Salamanders: Observers found eastern red‑back salamanders. These salamanders can bury deep in winter to stay moist in decaying roots, which helps them respire through skin.
- Honey mushroom (Armillaria): The group located honey mushrooms that, in summer, can bioluminesce (foxfire) with a green glow. In winter, the mushrooms typically do not glow — a seasonal “off” state.
Science explained (concise)
- Why lichens glow under UV: Certain chemicals in lichen reflect/emit visible light under UV; these compounds also serve as protection against ultraviolet damage (functionally like sunscreen).
- Bioluminescence in fungi: Some mushrooms emit light (bioluminescence). One hypothesis is the glow attracts animals that eat fungi and later disperse spores (i.e., advertising to dispersers).
- Schizophyllum commune mating system: This fungus has an extremely large number of mating types (tens of thousands), a reproductive strategy that increases outcrossing opportunities.
- Salamander winter survival: Many woodland amphibians use microhabitats (buried in roots, under logs) to stay moist and conserve energy; skin respiration requires moisture.
People, tools, and community science
- Guides and contributors featured: Serenella Linares (mycology/nature‑center lead), Natalie Howe (USDA ecologist), Matt Felperin (roving naturalist), Anna Kahanui (Capital Nature co‑founder). Hosts: Emily Kwong and Burleigh McCoy.
- Field tools used: UV flashlights for fluorescence, mercury‑vapor lamp + sheet for attracting moths, headlamps, and smartphone apps for identification.
- Apps and events recommended: iNaturalist for recording/identifying observations; community events like the City Nature Challenge and the Great American Campout to get involved with local bio‑blitzes and nature programming.
Notable moments & quotes
- Owl mnemonic (used for barred owl): “Who cooks for you? Who cooks for you all.”
- Reaction to lichen fluorescence: Described as “neon, like the Las Vegas strip” — vivid, surprising transformation under UV.
- Life lesson theme: Winter as a time of conservation — many organisms shut down or conserve energy (e.g., honey mushrooms not glowing in winter).
How to participate / action items
- Try a local night walk with guided naturalists or parks staff.
- Use iNaturalist to document and learn species around you.
- Join community events: City Nature Challenge (around Earth Day) or the Great American Campout to participate in organized observation sprints and outdoor activities.
- Check local parks/nature center websites for guided night hikes and moth‑lighting events.
Takeaways
- Even in winter, forests are biologically active and full of surprising phenomena visible with simple tools (UV light, lamp sheet).
- Fluorescence and bioluminescence reveal hidden aspects of organisms and often have ecological functions (protection, spore/seed dispersal).
- Community naturalists and citizen‑science tools make it easy and rewarding to notice, identify, and record local biodiversity — and people often reconnect with nature by acting like curious kids again.