How Flockline uses eBird sightings
Where the data comes from
Every sighting comes from eBird , the citizen-science database run by the Cornell Lab of Ornithology. Birders submit checklists of what they saw and where. Flockline reads that data live through the eBird API, so the map reflects what people have actually reported in the last few days, not a fixed dataset.
Reading the map
Pick a species from the title at the top, a window from the presets at the left, and states from Menu. Each dot is a location where that species was recently reported, colored by how recent the report is: blue for older, gold for mid, red for freshest.
eBird's live feed returns one record per location, the most recent report from each spot. A dot count is the number of distinct locations a bird turned up at, not the number of checklists and not the number of individual birds.
The birds figure beside it is a different thing: the sum of the counts birders actually typed in. Plenty of checklists record that a bird was present without saying how many, and those contribute nothing to it. So that number is a floor too, and always lower than the birds really out there.
The timeline
The scrubber animates movement over your chosen window, and the two modes answer different questions.
- Trail shows every location reported through the selected day, colored by recency. It is the full picture of where a species has been.
- New shows only the locations whose freshest report is the selected day, so you can watch fresh detections appear day by day. The bars above the rail count those locations for every day in the window.
Choosing a region
Nationwide selects all 50 states plus Washington, D.C. in one step. The other four presets follow U.S. Census groupings: Northeast, Midwest, South, and West. Choosing one selects every state in it, and the state buttons refine that selection. Northeast is the first-visit default so older links still work, but the map, timeline, Insights, and Ask all work at every scale.
Read the data honestly
This is the part worth internalizing. A sightings map reflects birder effort, not bird abundance.
- Common birds are under-reported. Many birders do not bother logging crows, robins, starlings, gulls, or pigeons. The map shows far fewer dots than where these birds actually are. Treat counts for ubiquitous species as a floor, never a total.
- "Reviewed" is not a quality score. eBird manually vets only flagged or locally rare reports. Common-bird records are auto-accepted and stay unreviewed, so a low reviewed share is normal, not a problem.
- Coverage is uneven. Well-birded hotspots and weekends produce more reports than remote areas and weekdays. Empty space on the map often means nobody was looking, not that nothing was there.
- State requests can fail independently. Flockline loads a large region a few states at a time. If eBird is temporarily unavailable for one state, the successful states stay on the map and a partial-results notice names what is missing.
- Provisional reports. Including unconfirmed reports adds recent sightings that have not been validated yet. Toggle it off in Menu to see only confirmed records.
Insights
Insights summarize eBird's notable-observations feed. Flockline generates the short summaries from those verified records and falls back to plain templated text if generation is unavailable. In both cases the species, places, dates, and checklist links come straight from eBird. The model only phrases what the data already says, and it is given the exact records so it cannot invent a sighting.
Scope and shareable links
Insights carry their own region and window, separate from the map. By default they follow whatever the map is showing; pick a region or a different window inside the panel and they stay pinned to it. The link button copies a URL that reopens Flockline directly on that exact view, so "rare birds in the West over the past three days" is one link.
My birds and field alerts
My birds is a device-local watchlist. Field alerts compare watched species against the current notable-sighting findings and appear inside the app. They are not push notifications and do not guarantee that every report will be surfaced. Watchlists, alert choices, preferred states, and filters stay in your browser and are not attached to an account.
Ask
The Ask assistant answers questions about birds and their recent activity. It is grounded: it queries the live eBird API through tools (species lookups, recent and notable sightings, sightings near a point) rather than answering from memory, so it will not fabricate sightings, counts, or locations. When you ask to see a bird, it can load that species onto the map and zoom to a real reported spot. Ask uses your selected states as its regional focus. If you say "near me" without naming a place, it asks for a town, park, ZIP code, or coordinates instead of assuming your location.
Freshness
Sightings are cached by state for about five minutes so the map stays quick and overlapping regional searches can reuse work. The refresh button in the top-right forces a live re-pull from eBird, bypassing that cache, when you want the very latest. Insights have a longer cache because they summarize a broader set of notable reports; the re-run button inside the panel forces a regenerate.
Privacy and shared links
Flockline does not require an account. Your active bird, states, timeline window, filters, open panel, and any pinned Insights scope are stored in the page URL so the view can be bookmarked or shared. No API credentials are ever stored in the browser. My birds and display preferences stay local to the device and are never sent with Ask questions. Questions submitted through Ask are sent to Flockline's server and to Anthropic to generate a response, so do not include personal or sensitive information in a birding question. If you subscribe to a weekly roundup, your email address and selected regional editions are stored by Resend for delivery. Flockline sends a confirmation link before adding the address, and every digest includes controls to change editions or unsubscribe.
Attribution and limits
Flockline is a viewer for public eBird data and is not affiliated with eBird or the Cornell Lab of Ornithology. It is meant for exploration and casual planning, not as a scientific survey. Sighting data is © eBird and its contributors. For the authoritative record, explore eBird .