Two different kinds of data. Push pressure is an estimate — what should be moving birds, from a freeze locking up water to the north, a front dropping through, wind out of the north. Bird counts and gaining/losing are measurements: official state survey numbers and how each area has changed since its previous survey. The estimate is the grid of cells underneath; the measurements are the outlined shapes and dots on top of it.

Why only the weather is shaded. Weather genuinely exists between our readings, so interpolating it across the map is fair — though cells fade with distance from a real reading, and anywhere more than 150 miles from one is left blank rather than guessed at. Bird counts are never interpolated, because the ground between two wetlands is farmland and towns, not half a duck. Each count stays exactly where it was measured: a dot for a single area, and for a regional estimate, the boundary the agency actually surveyed — no further.

Survey dates vary. Agencies survey on different cadences, so change is shown per day rather than per survey, and every marker carries the date it was measured.

Regional estimates are drawn as the ground they cover. An Arkansas survey zone or the Mississippi Delta is one number for a whole drainage basin, not a count of a marsh — those two things differ by a factor of thousands, so the map won't draw them at the same scale. Regions are shaded over their actual watershed (the USGS subbasins the agency flies as its survey strata); single areas stay a dot. Counts are written next to a marker wherever there's room, and more appear as you zoom in — marker size means nothing here on purpose.

Weights behind the score are engineering estimates, not validated against observed movement yet. Live weather from NOAA/NWS.