The quiet month of August, with the bird song all but over, heralds the start of the bird migration. Stover’s migrants will start to put on weight in the next few weeks in preparation for their long journey south. They will start to eat sugar-rich foods, such as rowan berries, elderberries and blackberries, in preference to insects. Look out for whitethroats on bramble patches, garden warblers eating elderberries and blackcaps pecking at rosehips. The adult swifts are already leaving Britain for their wintering grounds in the South. The young birds remain for an extra couple of weeks and then navigate their way back south unaided. The last swift over the lake was seen on 11th July. Swallows and house martins will start to group en masse this month.
On the heath, the nightjars are now rearing their second broods. Although the woods in the Park will seem very quiet, August is quite a busy time for many woodland birds. Many juveniles have now left their parents’ territory and are travelling further afield. They gather into parties with different species of young birds, learning where the best food sources are and trying to avoid predation. The adults are now undergoing a gradual moult to change their plumage. However, bullfinches can still be feeding young in August as many of the seeds on which they feed are ripe. Goldfinch, siskin, blackcap, crossbill and bullfinch were all recorded at Stover during July. Young sparrowhawk and tawny owl are now hunting for themselves and cash in on the abundance of young inexperienced birds, and moulting adults who cannot evade capture so well with some of their flight feathers missing.
The remaining three mute swan cygnets are doing well. The earlier broods of mallard ducklings are now the same size as their parents. Ducklings were still hatching out during last month. Moulting drakes are still in their ‘eclipse plumage’ which means they are hard to tell apart from the females; they will soon re-grow the vivid green plumage on their heads. The great-crested grebes built a nest and laid 4 eggs by 22nd July. The chicks, also known as ‘humbugs’ due to their stripy appearance, are due to hatch any day now. Moorhen have had a reasonable breeding season with five broods recorded so far, along with three coot broods. Moorhen numbers are now increasing as juveniles from outside of Stover move through the Park. Their numbers will peak in the winter. The mandarin ducks are still present on the lake with up to 25 being seen on 22nd July. For the first time three of the young have survived to adulthood. The first tufted ducks arrived on the 5th July – a reminder autumn isn’t far away! Kingfishers have been sighted throughout last month. Black-headed gulls were recorded nearly every day during last month along with small numbers of herring gulls. The black-headed gull numbers will start to increase for the winter along with the cormorants. A common sandpiper was recorded on 18th July. They usually stop off at Stover during August on their journey south to overwinter in Africa. However, a few remain in the South of Britain providing sightings in the winter.
Young hedgehogs are emerging now and setting off to lead independent lives. Small mammals such as voles and shrews reach peak numbers after their summer’s breeding. Most weasels give birth between May and August, so there are more around now than at any other time of the year. Weasels are much smaller than stoats and can follow a mouse or a vole into its tunnel. Roe deer were seen around the Park last month. Millions of flying ants will take to the air in August, and crickets and grasshoppers can be heard on warm evenings. Adders bask in the sun on the heathland and will give birth to live young (the eggs hatch immediately) in August. Grass-snakes were recorded on a couple of occasions during July in the marsh and swimming in the lake.
Clouds of butterflies and dragonflies are now on the wing. The first silver-washed fritillary sighting was on 11th July (5 days later than last year). There haven’t been any sightings of white admirals since April, and no marbled whites. One marbled white was recorded in 2019 which was only a slight improvement on the previous few years when none were seen. The first comma, large skipper, small copper and ringlet were spotted on 5th July, with the first brown argos on the 10th, gatekeeper on the 11th and speckled wood on the 25th. Painted Ladies have yet to be spotted. They were seen in 2019 when the heat wave bought them across the channel in their thousands, and previously in 2010. This butterfly can be a regular migrant to Britain from south-west Europe and North Africa, but only when favourable conditions exist on the continent do their numbers swell to produce a larger influx into Britain. The darker form of the comma butterfly can now be seen which is produced in response to shortening day length and will hibernate over the winter. The second brood of brimstone butterflies should just have emerged from eggs laid earlier this year. The larval food plant is alder buckthorn growing in profusion in the Park’s heathland. Red Admirals migrate from the Mediterranean and as soon as they arrive here the females lay their eggs on the nettles. In August the caterpillars will have turned into adults so there should be a peak of red admirals this month. The first red admiral was recorded on 5th July which is unusually late. Keep an eye out for the scarlet tiger moth. This day-time flying moth has bright red under-wings as its name suggests. If it is disturbed by a predatory bird it shows off its bright hind-wings to startle the bird as it escapes. It can also defend itself from lizards by secreting two blobs of poisonous, bright yellow liquid from behind its head. Glow-worms should now be visible along the carriage drive and firebreak at dusk; four were spotted on the evening of 17th July.
August is the peak time for watching many of the more impressive dragonflies, such as hawkers, chasers and darters, which coincides with the emergence of many of the insects on which they feed. Keep an eye out for southern hawkers which are usually abundant in August. The first keeled skimmer was recorded on 4th July, with the first red-eyed damselflies on the 11th.
One of August’s spectaculars at Stover is the heather which is in full bloom at the moment. Other plants in flower include purple loosestrife, hemp agrimony, figwort, common centaury, valerian and fleabane which are providing nectar for the last of this season’s insects. In the past the stems and leaves of fleabane were burnt to produce smoke that helped to keep fleas away. Bladderwort can be seen in the lake and ponds. This yellow aquatic carnivorous plant has finely divided leaves which bear small bladders. These act like vacuum cleaners sucking in animals which trigger the mechanism. The southern marsh has provided a fantastic display of flowers during last month.
Nature is always one step ahead – take a look at the trees and you’ll see hazel and beech nuts, elder and hawthorn berries, and sycamore seeds amongst the leaves. They’ll need this month to ripen properly before the autumn when they become more visible as the leaves start to drop.
For the seventeenth year running Stover has been awarded the Green Flag by the Civic Trust. This award reflects the hard work carried out by all of the individuals and volunteer groups that help manage the Park throughout the year; a big thank you to all involved.