Things I've noticed recently:

• There are lots of spiders about, of all types.
• There are lots of Harvestmen about, including lots of big but short legged varieties that I haven't especially noticed before.
• Ants have started building large hills of soil around the garden. Including in the middle of low-growing plants, hence burying said plant!
• Plants are growing at a tremendous rate, probably because of all the rain recently, mixed with a decent amount of sun and warm temperatures.
• The leaves are turning and starting to fall from some trees. Autumn is just around the corner.
• Bird poo from those visiting feeders tends to kill the plants directly beneath. This isn't a seasonal observation specifically.