The data sample is 62 strong "A-B" calls from October 12 (day 285), 2001, scanned by hand. There are 48 "interior" calls, ones which are preceded by an "A-B" pair in the same sequence. The scanned time is accurate to only about one pixel (2 seconds), while the "fitted time" determined from the center of the envelope of the filtered call should be more accurate.

The results on this page can be summarized as follows. For this 2-1/2 hour long group of 62 A-B call pairs, the "B"-to-"B" separation of call pairs within sequences was about 135 seconds, with a standard deviation of about 5 seconds. (More careful statistics will be done later.) Breathing intervals were smoothly distributed from 160 seconds to 260 seconds. (n=13)

Time interval between calls. Most time intervals are seen to be near 135 seconds. A distribution of values going up to 250 seconds or so represents the "breathing intervals" between call sequences.

Time interval between calls, expanded scale. For each call, the time since the previous call is plotted using the scan time, and using the fitted time. This gives some insight into the precision of the time measurements. The difference between scan timing and envelope ("fit") timing seems to average about zero, with an rms deviation of 2 or 3 seconds. The calling interval itself appears to have a larger variation than this, implying that this variation is "real," not due to measurment errors.

Time interval between calls, for "interior" calls only. Here the envelope time is used. The period from 17:05 to 17:45 seems to show a wider varatiability in call spacing than the rest of the sequence. Inspection of the on-line spectrograms does not show any corresponding unusual features.

Time interval between interior calls, scale expanded even more; envelope time used. From this plot we can estimate roughly that the average time between "B" calls in this group of "A-B" calls is about 135 seconds, with a standard deviation of the set of about 5 seconds. Note that three intervals greater than 160 seconds fall off the visible region of the plot.

2-d plot of call intensity versus time interval, for interior calls. There is no indication that the less intense calls are badly measured. NOTE: this plot is for A-B calls of day\ 285, not for "Moby Jane."

2-d plot of call sequence number versus time interval. There is not evidence that the timing evolves during call sequences. (Envelope timing used.) NOTE: this plot is for A-B calls of day 285, not for "Moby Jane."

IDL program rdfit.pro used to make the graphs above.
IDL program pabdt1.pro used to make the graphs above.