The first day of astronomical autumn arrived last Tuesday with the Autumnal Equinox. From the Latin ‘aequus’ (equal) and ‘nox’ (night) equinox refers to the equal length of daylight and nighttime hours, after which nights draw in.
The shortening of daylight leads to the reduction of photosynthesis in deciduous trees, a change in leaf colour and eventual leaf drop. This beautiful spectacle is one sign of phenological autumn, along with other ecological and biological signs such as bird migration.
Unlike the other autumnal timings (meteorological and astronomical) there is no set date for phenological autumn. Therefore dates can change each year as weather and the climate impacts on it. The timing of the phenological signs can even differ from decade to decade.
For more information on phenology and how it has changed over time, please see the BBC website.
Phenological changes are studied by scientists who analyse data recorded by citizen scientists on the Nature’s Calendar, via the Woodland Trust, (signs of Spring are also recorded this way).
As I compose this post, I am aware of the mist outside, it certainly feels like an autumn morning. The weather this coming weekend is due to be cold and wet, giving me the perfect opportunity to cosy up and input my collected data to Nature’s calendar.
Bee in the Moment 