BirdCast

BirdCast reads nocturnal migration from the same U.S. radar network used to watch precipitation. Its live map estimates migration traffic rate after sunset, displays flight direction and marks radars that are unavailable. Forecast maps combine weather predictions with relationships learned from historical radar movements to anticipate intensity over the next nights. Local dashboards turn the continental view into county-level timing and totals, giving birders a reasoned signal for when a heavy flight may produce a busy morning on the ground.

The bright colours describe birds in active flight, not a species list or a guaranteed fallout at a particular park. Radar cannot name the migrants, rain can complicate interpretation, mountain installations leave coverage gaps, and the public maps cover the contiguous United States. Forecasts update as weather models change and should be paired with habitat knowledge and recent observations. BirdCast is most valuable for answering when broad movement is happening and for reducing collision risk through Lights Out action, not for promising which rarity will appear.