Fig. 4. Patterns of change across all species of aerial insectivores by year. Prior to 1980, trends show varying patterns, but trends become increasingly negative over time. Circles show the annualized trend between change points (from Figure 3, including the beginning and ending of each time series) plotted by the initial year. The sizes of circles are proportional to the square root of the duration of the trend (so larger circles represent trends over longer time periods). The horizontal (trend = 0) and vertical (year = 1980) lines are provided for reference. Trends are only shown for periods exceeding 4 years.