July 2014

water lily

Water lily
Sheila Sims

If you were a July baby you have a choice of two for your birth flower. One is the Larkspur, a spiky blue flower which used to be found in the corn fields of East Anglia, but is now rare in the wild; many of us, however, have a cultivated relative, the Delphinium, in our gardens. July’s other birth flower is the very fragrant Water Lily. Found in lakes, ponds and slow moving water, rhizomes on the bottom send up flexible stalks, bearing the leaves and flowers, which often form dense colonies, covering the surface. They provide shelter for many aquatic invertebrates which in turn are food for fish, reptiles, amphibians and water birds; deer and rodents will also feed on the leaves and rhizomes. It is a beautiful flower, one that compels us to stop and stare and that the artist, Monet, found irresistible. The paintings of his lily pond are probably some of the most familiar works of art.

A Native American legend tells us that a bright star turned into a maiden so that she could fall to earth and play with the children, but it seems that they were not very impressed. So she did another quick change and became a Water Lily, which the children loved! It must be true because American Indians are honourable people and never lie, especially to their children.

 Four-spotted chaser Sheila Sims

Four-spotted chaser
Sheila Sims

Some of the invertebrates that lurk under Water Lilies will be dragonfly larvae, called nymphs. These are the immature forms of the colourful hunters we see flying in the summer. The greater part of the dragonfly’s life is spent under water as a nymph, where it will feed on a wide range of aquatic creatures. When it is ready to mature it will climb up a plant, split its skin and emerge as a dragonfly. It will then pump fluid from its body into the wings until they are large and rigid enough for flight. There are two main groups, the larger ones, known as true dragonflies, are hawkers, chasers, darters and skimmers. Look out for the Norfolk Hawker, which has a brown body and clear wings and only occurs in the Broads; it is closely associated with the aquatic plant, the Water Soldier. A similar insect is the Brown Hawker, but this one has brown wings. The small, dainty dragonflies are damselflies which include a couple of species called demoiselles. The larger dragonflies are fast, athletic fliers and catch their insect prey by forming a net with their legs; damselflies tend to pluck their victims from vegetation. The mature insects do not live very long and now they must find a mate. The male will transfer his sperm to below his belly and, with claspers at the end of his body, he will grip the female by the head, or behind the neck, depending on the species. When she is ready she will loop round and collect the sperm with the tip of her abdomen.

 Azure damselflies about to mate Mike Sims

Azure damselflies
about to mate
Mike Sims

Damselflies often remain in tandem while the female lays her eggs by dipping the end of her body in the water; other dragonflies will place them in a slit in a plant stem. Sunny days are the best times to observe these beautiful insects.

And…
… when the sun goes in, the bats come out.

There are sixteen to eighteen species of bat in Britain, depending on which data you read, and numbers are boosted by immigrants from abroad. Thirteen types have been recorded in Norfolk and eleven of those are found in the Norwich area. Although there are some mammals that are said to fly, some tropical squirrels for instance, these animals are in fact gliding. Bats are the only mammals that truly fly and their wings consist of membranes of skin that are stretched between elongated finger bones. They are very efficient flyers, twisting and darting as they pursue their insect prey and can be seen in towns and cities, flitting around lampposts, catching moths and other nocturnal insects which are attracted by the light. If you have a pond in your garden this will also be liked by insects and bats will quickly move in.

Although we use the phrase ‘blind as a bat’ they are not, and their vision, like all nocturnal animals, is well adapted to low light. They use their sight to judge their height from the ground and to avoid predators and large objects; however, when hunting they use a sense called echolocation. A bat will emit very high frequency sounds, way beyond our range of hearing, which bounce off an insect and send back an echo to be picked up by sensitive ears. This will tell the animal the position and the size of the prey and whether it is hard or soft bodied. Even a tiny midge can be detected by this incredible system.

Like all mammals bats are furry and warm blooded and the babies feed on their mother’s milk. When at rest during the day they hang upside down from a roof or beam, and they are able to do this without getting a headache because of adaptations to their circulatory system. A bat has an extremely large heart, relative to its body size, enabling it to increase the amount of blood pumped around when flying, which requires  a great deal of energy, but when roosting during the day the heart rate drops dramatically. During hibernation in the winter, necessary because there is very little insect food about, it drops even further; in some species it will go down to as little as four beats a minute. They use many different roosting places, caves, hollow trees and man-made structures such as out-buildings, churches, and tunnels; they will also hang out under bridges. It is illegal to disturb bats and many a well-planned building project has been held up, or even refused when they have been found to be in residence.

Myths and bats go hand in hand, mainly due to ‘Dracula’, Bram Stoker’s famous book about a vampire. Vampire bats do exist and, although they have been known to feed on human blood, their main source of food is from sleeping animals. They are found in Central and South American countries, Mexico and some Caribbean islands – they definitely avoid Norfolk! Oh, and that story about bats getting tangled in your hair? Well, they would have to be very ill to do that, they normally know exactly where you are! While on holiday in the Caribbean island of Grenada, we were exploring a disused sugar mill and disturbed a colony of hundreds of large bats. The air was full of them, so close we could feel the breath of their wings on our faces. Not a single bat touched us even though they were obviously in a panic. So don’t worry and enjoy your evening visitors.

The free flying White Storks at Thrigby Hall, near Great Yarmouth, have not, as far as we know, produced any eggs in their nest on the chimney. They are young birds so maybe they are just practising for the future.

Although our four cathedral Peregrine chicks all fledged successfully, leaving a very untidy nest behind them, sadly, the last one to go was found dead in a nearby garden. A post mortem is being carried out at the time of writing. Hopefully we will see these stunning raptors return next year.

Things to do this month include:-

  • Dragonflies and Damselflies – Upton Broad and marshes.
  • Water trail and pub supper – Hickling Broad.
  • Summer treasure trail – Cley marshes.
  • Details at Norfolk Wildlife Trust www.norfolkwildlifetrust.org.uk or call 01603 625540
  • Pod dipping and guided walks – Holkham Nature Reserve ticketoffice@holkham.co.uk or call 013128713111
  • Beginners birding – Titchwell Nature Reserve – 01485 210779

© Sheila Sims.   Email: sheila@norfolknaturediary.uk

 

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