Stuart Bullen: A busy summer season for nature

Bee'Photo: BBCT EMN-141006-141246001
Bee'Photo: BBCT EMN-141006-141246001

Summer is here. Or is it? Depending on who you ask, you will get a different answer.

British Meteorologists would give you the first specific calendar month when the temperatures get warmer, while the Irish national meteorologist service gives the 1st of May. A Chinese astronomer would shake his head and disagree. He’d say to you the 5th of May. Ask a Scandinavian weather forecaster and he will tell you, no, summer starts when the temperature reaches above 10 C for seven consecutive days, which means our summer started a month ago, or even as early as April if you go off temperatures recorded then. Question a school kid and he’d say mid July when the schools break up till September.

Everybody has their own marker for summer.

For me it’s the time of year when the fields spring to life with the vivid life affirming colours of the wild meadow flowers. From the bright letterbox red of the poppies, the spiky purple hairdo of the first knapweeds through to the Persil brightness of the white campion; roadsides and verges teem with Burnet moths and fritillary butterflies. As more flowers begin to bloom in June than at any other time of year, the air is filled with a rich heady floral perfume, the buzz of bees and the melody of birdsong heralding the start of summer.

The woods are noisy with the sound of birds and their young. You may still hear cuckoos, the bringer of spring, if you listen out for them. These weird looking birds (look like a deranged pigeon wearing a stripy tank top to me) will be with us until August. Their ubiquitous call from which we get the bird’s name, it’s an onomapoeia word – named after noise it makes- is best heard in the early evening.

Down by 59% the cuckoo is becoming less and less a common visitor to Bourne and other places in the UK. No conclusive reason can be given for the decline, though increased use of pesticides in farming over the decades could be decreasing the number of caterpillars that they feed on, hence having a knock on effect on the cuckoo population.

The cuckoo is famous for its antics in other birds’ nests. A female cuckoo can lay up to 25 eggs, which would take a football stadium of a nest to lay them in and an impossible task of trying to feed them when they hatch. By laying them singularly and spread around in other species’ nests, she is actually

increasing the survival rate of her offspring. She chooses a nest to use, waits till the parent bird is away and quickly flies in and removes one egg from the nest and lays an egg and then goes. The whole thing lasts around ten seconds. The other birds not only keep the eggs warm but feed the chick when it has hatched. Reed warblers, meadow pipits and dunnocks are the most commonly parasitised, with the female cuckoo laying eggs which match in colour and pattern the host bird’s.

This ability is passed on through the female genes only, with the bird species a cuckoo is born into used by the same cuckoo when it’s mature enough to lay eggs herself.

The egg is a visual trick which fools the host bird. But when the cuckoo chick hatches, it chucks out the original eggs and any nestlings from the nest and then cons the “adopted” parents into feeding it with a quite clever vocal trick. As the chick is bigger than the hatchlings it has evicted, it obviously needs more food. One study from Cambridge University a few years ago found that the cuckoo chick makes a rapid begging call that could be mimicking a whole brood of host chicks. This makes the host parents work hard to feed them. Mimicking alone wouldn’t be enough to feed enough though, so cuckoo chicks fledge later than other chicks, thereby getting the parent to feed it longer.

Rather clever birds.

As you wandered around your garden or lanes around Bourne, you won’t help but notice the number of bumblebees flying around. But you may notice one bumble bee that doesn’t seem to be as industrious as other bees as it hovers from flower to flower. It might look like a normal bee but on closer inspection, you might find its larger, has no pollen sacks on its legs and that its wings are much darker in colour than other bumblebees. This is a cuckoo but of a very different kind. This is one of a species of bee called cuckoo bumblebee. We have in the UK 6 species of them, with most of them found only in the lowlands of the UK, and they live up to their namesakes.

These bees emerge in late spring looking for colonies of other species of bumblebees. Then once a colony has been located, the queen cuckoo bee goes in and kills the resident queen. Then coating itself in pheromones, which give the worker bees and their hive their “identify”, the cuckoo bee starts to get the worker bees to feed her instead and look after her eggs she now lays. After the eggs have hatched, they leave the host colony to mate and find a new colony to monopolise.

There are many more things to watch out for this summer. Birds are visiting our gardens more regularly to feed their growing chicks at the moment. Butterflies, in a continual squabble over territories; give a more colourful interest to the garden, while in the warm evenings, mammals, such as bats and hedgehogs, can be seen foraging around.

Summer is the season where nature almost comes to our door. But just by spending a little extra time looking around at this time of year and getting to know one or two species, like the cuckoo, better, we will be able to enjoy summer that bit more.

Stuart Bullen, of Bourne, trained as a biologist at the University of Sheffield and has worked in the media. He is passionate about nature and the environment and he has worked on various conservation projects with Natural England and other organisations. When possible he likes to tramp around the local nature reserves and woods doing a spot of botany. He has recently qualified as a master gardener with Garden Organic.