In the Dixon count, there are usually 5 counting groups (parties). Each group spends from 6-9 hours counting birds in different areas. So the number of Party-hours ranges from 30 to 45.
Over the 26 years of the count, the average number of Party-hours is about 38.
Formal analysis of CBC data uses these adjusted values.
Choose Graph Data: Numbers of Individuals Number of Individuals per Party-hour Both
Note: The count was not done in 2020 due to Covid.