Phenology is the study of recurring natural phenomena*, such as those that occur with the changing of the seasons. The study of these phenomena has been going on for hundreds of years, to a greater or lesser extent. I doubt that I will have the tenacity of Gilbert White or Robert Marsham but it will hopefully make me more aware of the changing seasons and act as a good excuse to get out and about a bit more.
The Woodland Trust have set up Nature's Calendar, for budding (geddit?) phenologists to gather information and submit it to a central point for collation. You can also view data collected over previous seasons, overlaid on a map of the UK. You can join on line and they will send you a guide with handy illustrations to help you identify species.
The sorts of seasonal changes that you can report include bud burst of common trees, the first flowers, nest building of birds, fruit ripening, frog spawn appearing, and so on. All the sorts of things that people out in the garden or walking in the countryside can note.
Kew gardens started a new initiative in 2000, gathering information on the flowering times of 100 plants in the gardens. But it is the long term historical data supplied by Marsham and other keen amateur phenologists that shows gradual changes in the times of first leaf and other signs of spring, a sign of climate change.
So, get out in the fresh air and start gathering data - it could be the start of a life-long obsession with phenology.
* I can't say or type the word 'phenomenon' without thinking of the Muppets sketch below**. Please do not blame me if it gets stuck in your head.
**apparently the music was composed for an Italian documentary about life in Sweden, called 'Sweden, heaven and hell' (except in italian, obviously).