It’s a sure sign that summer is here when the swallows come back from their winter quarters in Southern Africa. Many return to the same place where they nested last year, or where they were born, and by now most will have young. Swallows feed almost entirely on insects caught on the wing, sometimes flying high and sometimes low, dipping over water and zipping over fields catching their prey and it is said that a swallow will eat 60 insects an hour. (I want to know who counted them and how!) Whatever, they certainly consume a lot and have to catch even more when feeding their young. If the weather has been dry, and I don’t think we can say that this year, it will help the swallows if you create a mud pool so that they can build their nests which are composed of mud pellets reinforced with grass.
Another sign of summer is flies. Although the swallows like them the same can’t be said for ourselves. They are a nuisance buzzing round the kitchen and landing on our lunch and goodness knows where they have been before that; muck heaps, dog poo and dead things are just a few places that these flies like. They are the ones we are most aware of but there are over 7,000 species of flies in Britain and their life styles vary considerably. Some are parasitic, laying their eggs inside other insects or under the skin of animals and some bite and feed on blood. Others are nectar feeders and in the process do the valuable job of pollination. The blowflies, blue and green bottles, and house flies also are helpful in as much as their larvae will consume dead and decaying matter. Some also lay their eggs on living animals if they become soiled, which is not quite so helpful. Sheep are often victims of blowfly strike and when working in practice I have seen dogs that suffered as well, but the main patient was the rabbit. It always seemed to be on a Saturday morning when, after a week at school, during which bunny just sat in the corner of his hutch, the children took him out and made the grim discovery. Not a pleasant job to clean him up but we got on with it as quickly as possible to alleviate his suffering. Having said all that, flies are part of the food chain and therefore play an important part in the big picture.
A more likable insect that we see in summer is the ladybird but there is one that is not so likable – the Harlequin. Because this one has a voracious appetite it was imported from Asia to America in the 1980s to control aphids that were destroying crops and then from America to Europe for the same reason. It arrived in Britain in 2004, either accidentally carried or blown by the wind. It took only ten years for it to spread across the country which is the fastest insect colonisation ever recorded. The reason why it is undesirable is because, as well as aphids, it also eats the eggs and larvae of our own native ladybirds and those of some moths and butterflies. It is larger than most British ladybirds but there are many variables of colour; red with black spots, black with red spots, black with yellow spots are just a few, in fact over 100 different colour patterns have been recorded. Because of this it is not always easy to recognise and therefore control is difficult. Grey squirrels, American mink and Signal crayfish are all examples of the dangers of introducing alien species to foreign environments and the Harlequin ladybird has now been added to the list.
It could have arrived here on a plant from abroad, like the Oak processionary moth which is spreading out of London where it was accidentally brought from southern Europe. Although strict management programmes are in place it is still spreading rapidly and it seems from reports that it is only a matter of time before it reaches East Anglia. It was almost certainly introduced as eggs on an imported oak tree (haven’t we got enough of our own!) and the hatching caterpillars can strip all the foliage from the trees which leaves them vulnerable to disease and other pests. Other than that damage these caterpillars do, they are also responsible for another major problem. They shed hairs which are the cause of severe health problems in some people and animals, such as sore throats, skin and eye irritations, asthma and breathing difficulties. People have been advised not to touch the caterpillars and if there is accidental contact and an allergic reaction occurs, they should seek medical advice. This moth gets its name because the caterpillars move about, nose to tail, in processions of sometimes hundreds. This is one way that they can be recognised, others are that they have long, white hairs and they only feed on oak leaves.
The Brown-tail moth caterpillar, which causes similar health issues with its hairs, is native to Britain and has been a problem in Norfolk, particularly along the coast in Cromer. Paths have been roped off so that those insects nearby can be dealt with; this one feeds on a variety of plants in the rose family.
A foreign invader, which we have talked about before, is back in the news – Japanese knotweed. In spite of eradication trials by Swansea University, up to nineteen methods were tried over three years, the conclusion has been reached that there is no way to get rid of this highly invasive plant. Chemicals and physical removal were used and the only thing that proved effective in the control of knotweed was the herbicide glyphosate but this is very damaging to wildlife; it is hoped that new chemicals will be found. However, a Daily Telegraph reader said in his letter to the paper that he had achieved the removal of the devil-plant by constantly cutting it down and, although it took quite a while, it eventually gave up and disappeared. So, if you are unlucky enough to find it on your property, that might be worth trying; cut down every little shoot you see.
A more desirable plant you may find in damp places in the summer is Ragged robin, also called the Cuckoo flower because it blooms at the time when the cuckoo is calling. This very pretty, pink flower, sometimes white, is a member of the carnation family and loved by nectar feeding insects, particularly long tongued bees. Unfortunately, it is in decline due to changes in agricultural methods, the loss of ponds and the draining of wetlands. In the past it had several medicinal uses supposedly curing jaundice, stomach problems and many other ailments. Young girls used to give the plants the names of village boys and the first to flower meant that the girl who had named the flower would marry the boy she had called it after, a simple way to get your man!
Things to take part in this month include:
Beach clean – Cley Marshes.
Walk in Pigneys Wood – near North Walsham.
Children’s wildlife watch – Hickling Broad.
Evening Nightjar walk – Weeting Heath.
Release your artistic creativity – Cley Marshes.
Details at www.norfolkwildlifetrust.org.uk or 01603 625540.
© Sheila Sims 2018. Email: email@example.com