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.
The first house martins were first recorded on 7th April, joining the swallows and sand martins that arrived in March. Usually they all arrive by the end of March but this spring’s cold wet weather delayed many of the migrants as happened in 2023. The first blackcap was heard singing on 29th March with the first willow warbler yet to be recorded. Migrants still to appear include garden, willow 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.
The unseasonably cold wet weather caused many birds to stop nesting, however the ones that managed to incubate are now feeding young with the first warblers, blackbirds and robins due to fledge this month. The first blackbird feeding young was recorded on 6th April, with the first fledgling on the 22nd. Goldfinch and siskin have been recorded throughout April.
Two broods of duckling hatched out in April joining the previous two March broods. Most of the mallards are still sitting on eggs, along with coots and moorhen. The first coot chicks hatched out on 20th April, with the first moorhens two days later. The great-crested grebes are nest building in the marsh and the two adults can be seen most days fishing. 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 at the end of March, and as the eggs usually hatch after five weeks’ incubation, they should be due during the first week in May. Another pair of swans arrived on 13th April looking for a home but were chased away by our resident male. There have been up to five male mandarin duck at Stover – visible on the lake and ponds, with the females presumably sitting on eggs. Small numbers of tufted duck stayed until 17th April and then left for their breeding grounds in north Europe and Russia. Black-headed gulls have now left the lake, however there have been up to 4 herring gulls present throughout last month. Common sandpipers are usually seen at Stover in April, but not for the past few years. 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. Most of the over-wintering snipe have now left Stover. The small numbers of goosanders left the lake at the beginning of March.
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. Small tortoiseshells would normally be out by now but haven’t been spotted so far. 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 also 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 12th April, followed by the first beautiful demoiselle on the 19th. 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 – although the murky water caused by the dredging will make it a little harder this year. The smooth shelled and red-eared terrapin are yet to be seen following their winter hibernation; the red-eared terrapin is usually spotted around 25th March. A grass-snake was spotted in the outlet channel on 13th April along with two lizards in the woods.
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. Otherwind pollinated trees, such as oak and beech, flower before their leaves obstruct the drifting pollen. Holly, horse-chestnut, elder 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.