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. 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 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.
Now is about the time when the swan cygnets become susceptible to botulism. Please inform the rangers if you notice any of them separating themselves off from the others as this is a sign that not all is well. It is worth being aware that white bread is not suitable to feed the wildfowl as it contains yeast which can cause digestive problems. Whilst it isn’t directly responsible for wildfowl deaths, it does make it harder for them to fight infections as they are not as healthy as they could be. The saying ‘we are what we eat’ goes for animals and birds as well as for us humans !
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. 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 20 being seen on 24th July. Five mandarin ducklings hatched out on 17th July and one of these has survived. There have been up to 7 tufted ducks on the lake during July. Their summer numbers are gradually increasing with 2021 being the first year that they have been recorded during every month rather than being absent for the summer when the majority fly back to Russia to breed. Kingfishers have been sighted throughout last month.
Black-headed and herring gulls were present on most days during July. The black-headed gull numbers will start to increase for the winter along with the cormorants. Keep an eye out for common sandpipers this month as 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. 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 grassland areas and swimming in the lake.
Clouds of butterflies and dragonflies are now on the wing, making the most of the heatwave and the still unusually hot sunny weather (for the school holidays !) since. There have been more sightings of silver-washed fritillaries, but no white admirals this year since. The first marbled white was recorded on 19th July. Painted Ladies have yet to be spotted – it was anticipated that the heat wave would bring them across the channel as happened in 2019 when they arrived 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. 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.
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.
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 centuary, valarian 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 this summer.
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 nineteenth 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.