is a critical month for many plants as they attempt to produce viable seed before the first frosts. Rowans and spindles covered with berries are striking evidence of this. September is equally critical for many animals as they gather in food to sustain them through the winter, and in woodlands you are likely to see grey squirrels or jays burying acorns and other nuts.
By September most of our migratory birds have flown south to warmer parts. Sometimes the adults leave first and their young follow later on when they have built up their strength – cuckoos and swallows are examples.
Those birds that remain here over winter are busy fattening themselves up for the difficult months ahead. Feeding parties of tits work their way through the trees, sometimes accompanied by treecreepers or goldcrests. In weedy field corners, flocks of goldfinches feed on the seedheads of thistles and other flowering plants.
Early in the month is a good time to see brown hairsteak butterflies as the females come down from the treetops to find nectar before laying their eggs on blackthorn. In some years a second generation of clouded yellows or painted ladies may be emerging.
September brings the main harvest of edible fungi. Ceps, also known as penny bun mushrooms and among the most sought after, come up all through the month in good years, followed late in the month by wood blewits and many other species.
Look for galls on the underside of tree leaves. These are home to the grubs of many species of insect that have developed from eggs laid earlier in the year. They will spend winter in the soil after the leaf falls then pupate and emerge as adults next year to continue the cycle.