May is the month when the rhododendron, azalea, and yellow flag start to flower; the trees come into leaf; the last of the summer migrants return and when the dawn chorus is at its peak.
Nightjars usually start arriving from their winter quarters in Africa in May. The males arrive first usually during the first week of May, with the females following in mid-May. These nocturnal birds roost on the ground in heathland areas during the day and feed on moths at night. When glimpsed at dusk the nightjar resembles a large swift and can be heard ‘churring’. Keep an eye out for the real swifts which also return from Africa this month – make the most of them as they are the first migrants to leave in August.
Following behind the sand martins and swallows which were recorded in April, the first house martins were seen on 6th May. The first blackcap was heard singing on 26th March with the first willow warbler on 1st April. Migrants still to appear include garden and wood warbler, sedge warbler, spotted flycatcher, pied flycatcher and hobby. Hobbies are our only full-scale sub-Saharan migrant falcon. They arrive here this month and feed not only on birds, but also on insects, especially dragonflies. Their breeding season begins in early May with their chicks often just fledging in mid-August. This is an excellent time for them to learn to feed as there are plenty of young swallows and martins to chase as well as lots of dragonflies.
Many birds are now feeding young with the first warblers and robins due to fledge this month. Goldfinch and siskin have been recorded throughout April, with a male crossbill spotted near the Visitor Centre on the 11th. A male grey wagtail has been regularly seen at the the reedbeds during latter half of April.
There are several broods of ducklings on the lake – the first brood hatched out on 17th April, with some mallards still sitting on eggs, along with coots and moorhens. The fist moorhen young hatched on the 1st, with coot young on the 25th. A great-crested grebe arrived on the lake on 18th April, followed by two more on the 20th. One left on the 24th as three was a crowd, and the remaining pair have been displaying. Great-crested grebe courtship is worth watching – they fluff up their ruffs, shake their heads and present each other with water-weed staying beak to beak. The female swan started sitting on 21st March which is the earliest record to date. The eggs usually hatch after five weeks’ incubation. There have been up to five male mandarin duck at Stover – visible on the lake and ponds, with the females presumably sitting on eggs. The pochard, tufted ducks (last recorded on 17th April) and black-headed gulls have now left the lake, however there have been up to 60 herring gulls present throughout last month. There was a sighting of common sandpiper on 25th April. This bird is the most likely wader to be seen inland. It is a summer visitor and is easily told by its typical flickering-wing flight low over the water, and habit of bobbing its head up and down when at rest. It is usually seen at Stover in April. A solitary snipe was recorded on 11th April in the marsh. Most of the over-wintering snipe have now left Stover. The goosanders left the lake on 15th March; in previous years they have stayed until the beginning of April.
Following the appearance of their aphid prey many species of ladybird have started emerging from their winter shelters. April has seen an increase in butterfly numbers. The first peacock was spotted on 2nd April, comma and orange-tip on the 14th, speckled wood on the 21st, and dingy skipper on the 25th; joining the brimstones which appeared in March. Keep an eye out for holly blues which should be on the wing at the moment and can be easily mistaken for common blue butterflies. The rare white admiral butterfly should be on the wing this month. White admirals spend a lot of time in the tree canopy but will also come down to ground level where they feed on bramble blossom. Honeysuckle is important to these butterflies as it is the caterpillar’s food plant. Pearl-bordered fritillaries should also be on the wing this month but are declining nationally; they favour yellow and purple plants to feed from, with bugle being their favourite.
The first damselfly of the year, the large red damselfly, was recorded at Stover on 24th April. Other dragonfly species have yet to emerge. In particular look out for the rare downy emerald dragonfly which should be on the wing this month. The downy emerald is a handsome metallic bronze-green dragonfly with a distinct covering of yellow downy hair, which is particularly noticeable on its thorax. The male, who has a clubbed tail, patrols along the tree-lined margins of the lake and ponds.
Cockchafer beetles (also known as maybugs) are usually flying around in May. They are mainly nocturnal and emerge during the middle of the month after spending the previous three years as a white, root-feeding grub. Stag beetles also start to appear in May after feeding in dead wood as larvae for five years. Once an adult they only live for a few weeks using this time to find mates and lay eggs.
With the increase in numbers of flying insects bats should start to become more conspicuous at dusk as they fly over the lake feeding. Hedgehogs court, and badger, stoat and fox cubs are active above the ground in May. Roe deer hinds will drop their kids from mid-May onwards. The young stay hidden among the bracken and grass, not moving until their mothers’ return. Many of the freshwater fish in the lake, especially the rudd and roach, can now be seen at the water’s edge as they spawn. The red-eared and smooth shelled terrapins are yet to be seen following their winter hibernation, presumably due to the colder than average weather conditions. There is a larger than usual rat population at Stover at the moment and visitors are asked not to leave food out in the marked areas. In previous years when the rats have increased the tawny owls have managed to rear more owlets – four were recorded in one box instead of the usual one or two – so hopefully the balance will soon be re-established. The buzzard was also seen taking one in the early morning.
The large Monterey Pines in the car park will soon start to shed huge quantities of pollen, covering the cars in a luminous yellow dust. Other wind pollinated trees, such as oak and beech, flower before their leaves obstruct the drifting pollen. Holly, horse-chestnut and hawthorn also flower this month displaying their more obvious insect-visited flowers. Just before the trees are in full leaf and shade out the woodland floor completely, the spring flowers have their chance to grow, flower and attract pollinating insects. Most are powered by food stored in underground bulbs or stems. These include bluebells, ramsons and violets which are already out in profusion at Stover. Common-spotted orchid leaves are just starting to appear. The ferns are now uncurling and the horsetails are coming up around the lake path and in the marsh. Cuckoo flower (ladies smock) is out in abundance in the marsh also. Along with garlic mustard, this plant is the orange-tip butterfly caterpillars’ favourite food plant, so keep an eye out for the single eggs which turn bright orange shortly after being laid. The marsh marigolds are in flower in the marsh. Yellow archangel and celandine are in flower along with sanicle, ground ivy, yellow pimpernel and herb robert. Lords-and-ladies are also in flower and give off a foul stench attracting the flies which pollinate it.