Fig. 2.

The numbers of observation events in April 2020 were largely consistent with the patterns of interannual change across prior years. Data points were the numbers of observation events within each hexagonal grid cell inside each political unit. The width of each vertical bar of these violin plots is a smoothed representation of the proportion of grid cells with a given number of observation events. White dots within the “violins” are the median number of observation events, and thicker black bars denote the inter-quartile ranges.