Noticed a couple of things over the last few days that may indicate a change in the seasons.

Firstly, i heard a bat noise - a loud high pitched tone - i haven't heard one for a while (a few months) and assume they must be migratory and have just returned.

Secondly, i saw the first fireflies of the season last night. There seems to be two kinds here - an autumn one (larger, with a green light) - and the spring ones (yellow light).