Every swarm report is a citizen science data point. Together, they form the most detailed picture of honey bee swarm activity in North America ever assembled, and a new way to understand where bees are thriving, where they're struggling, and where the season is heading.
The Contributor dashboard brings every data tool into one view, updated daily.
Honey bee swarms are one of nature's reliable seasonal signals. When a colony splits in spring and the old queen leaves with half the bees to find a new home, the timing, location, and pattern of that event reflect something real: the health of the colony, the quality of the winter, the temperature of the spring, the density of local beekeeping activity.
For most of beekeeping history this signal existed but couldn't be measured. Individual beekeepers kept notes. Local associations tracked calls. But there was no way to see the pattern at scale, across a region or a continent, year over year.
Swarmed was built to change that. Since 2022 we have collected over 17,000 georeferenced swarm reports from beekeepers across North America, each one carrying a GPS coordinate, a date, and an outcome. That dataset now underpins a set of analytical tools that are useful to beekeepers planning their season and meaningful to anyone interested in what the bees are telling us about the broader environment.
Honey bee swarms don't appear randomly. They cluster in predictable places: near established colonies, near natural cavities in mature trees, in landscapes that can support them. They follow the season with remarkable fidelity, tracking accumulated warmth rather than calendar dates. And they respond to disruption, whether a warm winter, a drought year, a change in land use, or a disease event in the local bee population.
Each of these signals is visible in the data.
Watch the current season unfold in the live North America bee swarm season report.
The 2026 swarm season arrived roughly 17 days earlier than 2025 across monitored North American regions, based on when accumulated Growing Degree Days crossed each region's historically learned swarming threshold. A second independent method confirmed it: comparing the shape of each year's swarm report curve, normalized to remove the effect of platform growth. Both methods produced the same result. This is the kind of finding that would have been invisible without a continental-scale observational network.
The geographic pattern is equally telling. California and Colorado counties saw their swarm seasons arrive weeks to months earlier than last year. Florida and the Gulf Coast tracked essentially unchanged. This asymmetry is consistent with recent experimental research on bee phenology (Ganuza et al., Functional Ecology, 2026), which found that populations from already-warm climates advance their seasonal timing more dramatically under warming conditions than cool-adapted populations. The bees in San Mateo County were not simply responding to a warm spring. They were responding the way San Mateo bees specifically respond to warmth, differently from how Florida bees respond to the same signal.
This is what population-level data makes visible that individual observation cannot.
The same data that underpins seasonal analysis is the foundation of a set of practical tools now available to Swarmed Contributors.
Every swarm ever reported to Swarmed, shown as a dot on the map. It forms a heatmap of historical density at low zoom and resolves into individual clickable reports up close. Locations where swarms appear repeatedly are not random: they carry residual pheromone signals from previous colonies and physical traits that make bees want to settle there. Knowing your local hotspots is the single most useful input for swarm trap placement.
Every morning, a swarm likelihood score from 0 to 100 is calculated for every monitored location, drawing on five weather variables and three habitat factors. The weather component uses the same Growing Degree Day methodology as agricultural pest forecasting, tracking accumulated biological readiness rather than calendar dates. The habitat component reflects historical swarm density, proximity to registered beekeeping activity, and mature tree canopy cover from satellite data.
A running comparison of how the current season is tracking against the historical average for your region. If your area is running 50% above expected through April, that tells you something useful about how to deploy your time and equipment for the rest of the spring.
A ranked list of the best places to set swarm traps within your catching radius, combining historical swarm density, distance from your apiary, local beekeeper density, and mature tree canopy cover from satellite imagery. Trap specifications (4.5 metre height, 40-litre cavity volume, southeast-facing entrance) are drawn from Thomas Seeley's controlled nest site selection experiments at Cornell University and Appledore Island.
Managed honey bees are, paradoxically, one of our better windows into ecosystem health precisely because they are so mobile and so sensitive to their environment. A swarm that settles and survives reflects a landscape that can support it. One that doesn't reflects something about resource availability, pesticide exposure, disease pressure, or the absence of suitable nesting habitat.
The Swarmed dataset captures something most ecological datasets cannot: the actual behavior of a large animal population across a continent, in near real time, at the scale of a neighbourhood. It is not a survey. It is not a model. It is a direct observational record of where bees went, when, and what happened next.
At current scale, the dataset is most powerful for tracking seasonal timing and geographic patterns at the county and state level. As coverage grows, with more beekeepers, more regions, and more years, it will become progressively more useful for finer-grained analysis: which urban landscapes produce the most swarms relative to their managed hive density, suggesting high feral colony survival; which regions are showing earlier seasons than their climate would predict; where the gap between swarm production and swarm capture is largest, indicating unmet demand or underserved beekeeper communities.
The monitoring infrastructure that makes this possible is the same infrastructure that alerts a beekeeper in Denver that a swarm appeared three blocks from their house this morning. The scientific value is a byproduct of the practical utility. That alignment is intentional.
Making this data open is the work of Citizens of the Hive, our citizen science initiative for pollinator research.
The seasonal advance finding is based on a weather-driven analysis comparing Growing Degree Day threshold-crossing dates across 56 monitored regions with sufficient matched swarm-weather observations in both 2025 and 2026. The threshold for each region, the accumulated warmth at which swarming historically begins, is learned from that region's own historical swarm report data rather than applied universally. Daily weather data is sourced from Open-Meteo.
Habitat scoring draws on three inputs: historical swarm density per H3 hex cell (approximately 0.74 km² each) from Swarmed's full report database, registered beekeeper density within 3km as a proxy for active colony density, and canopy height data from the Meta/WRI Global Canopy Height Model (Tolan et al., 2024), which identifies areas with mature trees structurally capable of hosting natural bee nesting cavities.
The 17-day seasonal advance figure was confirmed by a second independent method using normalized cumulative report curves, which controls for platform growth by expressing each year's data as a percentage of annual total rather than absolute count.
Full methodology is available at buzz.beeswarmed.org/season.
Swarmed is a swarm alert service that runs on data. The more swarms the public reports, the more accurate the predictions become. The more accurate the predictions become, the more useful the platform is to beekeepers and communities. And the more comprehensive the dataset becomes, the clearer the picture of what is actually happening to honey bee populations across the world.
Every data point starts with a sighting. Spotted bees? Report a bee swarm.
If you keep bees and want access to the dashboard tools, Contributor access is available on a pay-what-you-want basis. If you are a researcher or institution interested in the dataset or in collaboration, we would like to hear from you at info@beeswarmed.org.
The dataset is strongest in regions with consistent multi-year coverage. Findings from areas with sparse or single-season reporting should be read with that caveat in mind.
