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. Only one nest site has been located containing one chick. None of the first brood nest sites were located.
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.
The remaining two 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. Moorhen have had a reasonable breeding season with three broods recorded so far. 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 10 being seen on 1st July. One tufted duck was present on the lake on 11th 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. Five common sandpipers were recorded on 27th 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 6th July (2 days later than last year). There have been numerous sightings of white admirals and a single recording of marbled white which is better than the last couple of years when none were seen. The last year that painted ladies were recorded was 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. This summer’s heatwave has bought them across the channel in their thousands 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. The first sighting for this year was recorded on 7th July. Three rare dragonflies were seen at Stover during July, possibly travelling on the hot winds from the continent with the painted lady butterflies. A male scarce chaser was recorded on 5th July and is a new record for Stover. The males have grey-blue eyes instead of the darker eyes of the keeled skimmer, and it lacks the dark wing bases. It is usually found in East Anglia and the South. A male lesser emperor was seen the following day along with a red-veined darter. The lesser emperor is slightly smaller than the emperor and the male’s abdomen is not a continuous blue. The emperor dragonfly drives it away if encountered. Male red-veined darters as their name suggests have red veins in the inner half of their wings.
There have been no noticeable fish deaths this summer due to the hot weather which affects the levels of oxygen in the water. This may be because more fish dies last summer than was originally realised. However, as there are less fish disturbing the sediment the water in the lake has remained unusually clear to the extent that many aquatic plants are growing. The invertebrate life has never been so obvious with mayflies, pond skaters, dragonfly nymphs and aquatic beetles thriving as they are no longer being predated by the fish. The types of plants growing unfortunately do indicate that the lake has become nutrient rich which will need addressing.
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 sixteenth 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.