The Audubon Field Notes
reporting seasons are tied to months of the year. This
dictionary translates month numbers into season names,
which in turn connect the rendering of the index table to
the seasonal column color codes defined in Section 5.4, “Seasonal column markup rules: th.winter, etc.”.
MONTH_SEASON_MAP = {
'01': 'winter', '02': 'winter', '03': 'spring',
'04': 'spring', '05': 'spring', '06': 'summer',
'07': 'summer', '08': 'fall', '09': 'fall',
'10': 'fall', '11': 'fall', '12': 'winter' }