Fig 1.
The study area in southeast Norway consisting of the rivers Gvarv, Saua and Straumen, and lakes Bråfjorden, Nomevatn and Norsjø.
Red dots show the GPS positions of approached birds (group sizes are not indicated).
Table 1.
Total number of observed individuals, average group size, average FID, and body mass for the nine bird species approached during this study in southeast Norway.
Body mass was taken from the literature indicated in the last column.
Table 2.
The best model explaining the flight initiation distance in European waterbirds approached from a boat in 2015 and 2016 in southeast Norway, separately for (1) all birds species together, (2) goldeneyes, and (3) mallards.
β, estimated coefficient; SE, standard error; LCI, lower limit of the 95% confidence interval; UCI, upper limit of the 95% confidence interval; bold font indicates informative parameters.
Fig 2.
The predicted flight initiation distance (FID) of waterbirds (n = 196 approaches) in relation to the group size (top), the water body type (middle), and the starting distance (bottom) in southeast Norway in 2015 and 2016.
Grey shading represents 95% confidence intervals.
Fig 3.
The predicted flight initiation distance (FID) of common goldeneyes (top) and mallards (bottom) in relation to the interaction of water body type and starting distance in southeast Norway in 2015 and 2016.
Solid grey lines represent the predicted FID on lakes and dashed black lines the predicted FID on rivers. Raw data is shown with grey dots on lakes, and with black triangles on rivers. Grey shading represents 95% confidence intervals.