Changing the Date
Every layer on the map reads for one date. This is how you pick it.
The date control sits in the top-left of the map. Step a day at a time with ‹ and ›, or click the date itself to open a calendar and jump.
The calendar only lets you pick dates that actually have waterfowl data — days without coverage are not selectable, so you cannot land on an empty map by accident.
Whatever you pick drives the whole map: the density layer, the conditions readout at the bottom, and the roost read in the Spots pane all move with it.
What the Free plan includes
On the Free plan the date control is a dropdown rather than a full calendar, offering the 1st of each month — the twelve most recent months that have data. It is a monthly snapshot of the archive rather than a restriction on anything else.
Premium opens up every date with data, and with it the full multi-night roost read on your spot cards and the two-season track record on a spot's page.
Saving spots, logging hunts, the weather overlays and Bird ID are not limited by plan.
The Spots board has the same date control, and the same monthly-snapshot behaviour on Free — see Spot Historical Data.