A LITTLE WONDER AFTER DARK
When does the
night light up?
Watch the seasons echo through time.
Follow every month from 2021 through 2025, one year at a time, across all record types. Explore where records were concentrated as the seasons return.
FOLLOW THE SEASONS THROUGH TIME
FIVE YEARS. EVERY SEASON.
The rhythm of the records.
Each column is one year; each row is a month. Color shows the share of that year’s records in each month. Click a cell to visit its month and a window containing that year. Arrow keys explore neighboring cells. On smaller screens, scroll sideways to see the full timeline.
These are patterns in collected records. Changing search effort, collection methods and contributors can change the picture. Shares describe the archive; they do not measure population size or migration. A few records can produce a bright cell—check the sample size.
Behind the lights · data & credits
Records of wonder, collected over time.
Fireflies are beetles in the family Lampyridae. This independent explorer combines publicly available CC0 and CC-BY 4.0 records from GBIF’s contributing collections and observers. It includes museum specimens and observations, not just recent sightings. A genus groups related species; some fireflies do not flash as adults.
The historical atlas plays all twelve calendar months, pooling the same month across consecutive years. For example, June 1926–1930 combines June records from those five years; after December it advances to January 1927–1931. The final five-year window is 2021–2025. The clock labels the center year of the window (1928 for 1926–1930); the full range stays beside Play. All five years receive equal weight. Shorter selected ranges use the number of years available. The one-year option shows individual year-months. The map shows reported locations matching the current month, years, place and record filters. The side panel also reports the selected place’s share of U.S. records in the window. The month chart and calendar use shares for the selected place. The annual bars show unpooled counts by record type. The default is all record types over 2021–2025, shown as individual year-months at slow speed. The century preset opens specimens over 1926–2025 in five-year windows. Earlier years are available in the year controls but have much thinner coverage. The fast setting traverses the century in about 90 seconds; slower settings let you inspect individual months. The separate seasonal mode combines all dated years from the same CC0/CC-BY historical archive; genus and state filters still apply. Records can include larvae and specimens. Counts reflect collecting and reporting effort, not population size, abundance, or a forecast. No records does not establish absence. Compare patterns cautiously: coverage varies by place, time, and contributor.
Lights use GBIF’s interpreted public coordinates, projected onto the map without random placement, jitter, movement, or repeated decorative flashing. Identical coordinates share a light; larger lights indicate multiple records. A filled light includes at least one record with reported uncertainty of at most 10 km. An open ring means all records at that location have unknown accuracy. Missing uncertainty is not treated as zero. Open a light to see its date, type, accuracy and original GBIF record. When nearby lights overlap at the current scale, the dialog lists their records and individual reported coordinates. Select a state to zoom in; “Show all states” restores the full map. Arrow keys navigate between lights after tabbing into the map. Alaska and Hawaii are repositioned and resized as insets.
Coordinates flagged as problematic, explicitly generalized or withheld, outside the map, or with reported uncertainty greater than 10 km are excluded from lights. Counts and charts retain these records; “records mapped” shows the coverage for the current filters. You can also hide unknown-accuracy records with the checkbox. These are quality screens, not guarantees: old specimens may be georeferenced retrospectively and distinct records may use the same locality coordinate. Points do not show movement, population density, or confirmed absence in dark areas. In five-year mode, a record may reappear in overlapping windows. No date or location is interpolated.
States use GBIF’s spatially interpreted administrative area. The historical aggregate snapshot remains at state level. Its companion location snapshot includes eligible reported coordinates and original GBIF IDs, with dates limited to year and month; photographs, collector names, and free-text localities are omitted. The history snapshot includes year, species and record type, plus public rights-holder names and original-record links for attribution. GBIF’s checks cannot eliminate all identification, date, or location errors; different IDs may still describe the same occurrence.
View the GBIF query ↗ · Download this snapshot ↓ · CC0 public-domain dedication ↗
History data and attribution
Historical gaps remain visible. No sightings are interpolated. The month chart offers shares or counts on a common scale across the selected years and filters. This control does not alter the map’s locations. Dates are occurrence dates, not upload dates. The incomplete latest year remains in the downloadable archive but is excluded from the atlas. The source archive also retains all records back to 1884. Specimen records avoid the recent growth in casual observations, but collection effort and digitization still vary over time; a flatter count series is not evidence of stable populations. “Sparse sample” flags fewer than 30 records in the selected place and window; this is a display caution, not a statistical confidence threshold. Records with missing or invalid state/year/month and repeated identifiers are excluded; different IDs can still describe the same occurrence.
Download reported locations and coverage ↓ · Full history credits and original-record links ↗ · Download history aggregates and attribution ↓ · CC-BY 4.0 license ↗
History aggregates adapt the source data by grouping state, year, month, interpreted genus/species and record type. Preserve the supplied credits, license links and change notice when reusing them. No endorsement is implied.
Original seasonal snapshot contributors
Each occurrence in the original seasonal snapshot carries a CC0 license in GBIF. History uses only CC0 and CC-BY 4.0 occurrences. Dataset titles link to their publishers and citation details. This explorer is not affiliated with GBIF, Smithsonian, or Firefly Atlas.
State boundaries: U.S. Census Bureau, via US Atlas. Map license.