Fig. 2

The influence of the hydrological and climatic predictor variables on the timing of breeding. The influence of the hydrological and climatic predictor variables on hatching date (hatching day-of-year) in the white-throated dipper population in Lyngdalselva 1978–2015. a Mean relative river discharge at each territory during the preceding Dec–Feb (Winter Qnorm mean [17]), b the North Atlantic Oscillation (NAO) 10–21 days after the trigger date at each territory (Spring NAO [26], c the minimum ground water levels for the last 20 days before the trigger date (Spring groundwater mean [14]), and d the maximum Snow Covered Area (SCA) the last 30 days before the trigger date (Spring SCA sd (06)), where 0 is no snow cover and 1 is full snow cover. Solid lines denote the effect and vertical dotted lines denote the 5 and 95% quantiles of the raw data. The trigger date is defined as the first date when the daily air temperature exceeded 0 °C for five consecutive days