Population stats & trends
Population make-up — sex & age
Weather when seen
Refugia usage
Confirmed photos assigned to each mat (distinct adders on hover). Assign photos on each adder's page, or open the Map.
Active season & hibernation
Extrapolated from the first and last sighting each year — a proxy for spring emergence and the autumn return to the hibernaculum. Adders are cold-adapted vipers that overwinter underground, so a near-absence of winter records reflects hibernation, not disappearance (see the review).
Amber = observed active span; the cool band is the inferred hibernation period. These are minimum active windows — true emergence/ingress may fall a little outside the first/last records, and are sensitive to survey effort.
Who was around when
Each row is one adder — the line is its known active span, round dots are encounters (a day's photos count as one), purple diamonds are life events. Tap any marker for details. Zoom with ＋/－ then scroll sideways; amber bands mark the active season (spring–autumn), cool bands the winter.