This plot shows the number of birds and mammals described per year. The Y-axis in this plot is the natural log of the number. One (1) is added to all numbers. This makes the years with zero values plot as zero [the Ln(0) = infinity; Ln(1) = 0]. The structure in the plot is somewhat obsucured by the large number of points and the overlap of the data. The lines drawn are smooth fits of the points (using an SPlus function "supsmu"). The next plot shows the same data, with the points removed and only the smooth fit lines drawn.