geom_peak               Visualise peaks in a power spectrum or
                        periodogram
ggetho                  Prepare a ggplot object to represent
                        behavioural data
ggperio                 Prepare a ggplot object to represent
                        periodogram data
ggspectro               Prepare a ggplot object to represent
                        spectrogram data
id_labeller             A facet labeller for 'id'
stat_bar_tile_etho      Display a variable of interest either as a
                        colour intensity value or as a bar height
stat_ld_annotations     Compute and display light/dark annotations onto
                        a plot object
stat_pop_etho           Compute and display a population aggregate for
                        a variable of interest
time_scales             Scales for durations
