Here's some edited info from
http://recording.phenology.org.uk/autumnwatch/:

"The BBC and the Woodland Trust are continuing their survey of the seasons and are now tracking the arrival of autumn across the UK. Together they are inviting everyone across the country to watch out for six key events in their region. This will help to build the most complete picture of the season unfolding across the UK, enabling scientists to understand how autumn is changing and what needs to be done to help wildlife thrive in the UK.

All the information you provide will contribute to over 300 years of observation and push forward ground breaking research into the impact of climate change on the natural world. You can get more information about this research on the UK Phenology Network website The findings of the Autumnwatch survey will be revealed in a new BBC TWO programme, Autumnwatch with Bill Oddie in late October. Everyone who makes a record, and gives their permission for further contact from the BBC and the Woodland Trust, will also receive updates on the latest findings and programme information."