November and the days are getting shorter and colder. This is the time of year when many animals are starting to hibernate, driven to do this because of the lack of food in the cold weather. Hibernation may seem like a long sleep but it is different because although there may be slight physical changes during sleep, in hibernation metabolism, temperature and heart rate drop dramatically. There are only three mammals in Britain which hibernate, hedgehogs, dormice and bats. During hibernation a Hedgehog will only breathe every few minutes and its body temperature will drop from 35C to 10C; the heart beats just 20 times per minute, the normal rate is around 190. This all happens to conserve energy and enable the animal to eke out its fat stores to keep it alive during the winter. However, a mild spell will sometimes bring a Hedgehog out in search of something to eat. If you see one at these times you can help by putting out some food; the specially formulated tinned food ‘Spike’s Dinner’ or some cat food would be very welcome. A Hedgehog will build a winter nest, called a hibernaculum, in a sheltered place, such as heaps of leaves or woodpiles, which is why it is important to move bonfire material before burning. If you should accidentally disturb a hibernating Hedgehog, cover it up quickly and leave it alone. They are very much in decline and the hot, dry spell we experienced this September didn’t help. It meant that there was a shortage of insect food at an important time and many may not have been able to put on enough fat to see them through hibernation. Animal rescue centres are seeing a lot of underweight animals brought in to be cared for, particularly young ones.
Although dormice spend most of their time in trees and hedges and build their summer nests there, in the winter their hibernating nest will be at or below ground level. The temperature is more likely to remain constant here and, like the Hedgehog, the mouse’s metabolic rate will drop significantly. The Dormouse will remain in hibernation for at least six months, from November to late April or early May, depending on the weather. These lovely little animals are also in decline mainly due to loss of ancient, connected woodlands.
Bats will hibernate in roof spaces, caves, church towers, hollow trees and any similar places which remain cool throughout the winter. They will not emerge until the spring when their insect food will be on the wing.
Snakes, lizards, frogs, toads and newts are all cold blooded animals, called ectothermic, which means that they cannot generate their own heat in the way that mammals do. They have to acquire warmth from an outside source, usually the sun, so they too will go into dormancy during the cold weather when there is no heat and little food. Research conducted by the charity ‘Froglife’ has found that the toad population has fallen by nearly 70% since the 1980s. Modern farming methods that saw the loss of many ponds, pesticides that kill the toads’ prey and traffic deaths, in spite of the teams of volunteers who carry the animals safely across busy roads during the breeding season, have all contributed to the decline; another reason is thought to be that milder winters have disrupted life cycles.
Some invertebrates also hibernate. Snails retreat into their shells, sealing the entrance to avoid loss of moisture and hiding in protected places; the Garden snails sometimes cluster together in nooks and crannies. Some bees make burrows and ladybirds gang up in crevices such as window frames.
Many butterflies spend the winter as eggs, caterpillars or pupae but some will hibernate as adults. The Brimstone will hide in ivy or similar thickly growing plants, while the Small tortoiseshell and the Peacock can often be found in cool outbuildings. Unfortunately, this years Big Butterfly Count has shown a great drop in the number of butterflies countrywide.
Some animals, badgers and squirrels for example, may spend sleepy days in their nests during the winter but they are not hibernating, merely avoiding bad conditions; they will be up and about foraging or eating stored food during better weather.
There is certainly a great deal of stored food around our house. Our Walnut tree is not a nut tree anymore – it’s just a tree. A team of three squirrels worked hard one morning stripping it and burying their bounty in the garden and neighbouring field, driving our three Lurchers to the point of nervous breakdown. The little robbers left ONE nut, high up in the tree, but I see that has now gone as well. Perhaps, this winter, they will leave the bird food alone!
Blackbirds are also busy in the garden feeding on windfall apples; I counted fifteen around one tree. Although they can be very aggressive to each other, these were being quite tolerant, probably because each one had its own apple.
Everyone, I think, will recognise a male Blackbird with his glossy black plumage, deep yellow beak and eye ring but the female is not so easy. She is brown with a speckled breast and is sometimes mistaken for a Song thrush to which she is related; juveniles are also brown. Blackbirds feed on a variety of insects, fruit, berries and earthworms which they often have to tug out of the ground. There has been much discussion on whether a Blackbird can actually hear a worm moving in the soil. It certainly looks as if it is listening when it cocks its head to one side but, as the eyes are on the side of the head, it has to do this in order to see any movement. So the general consensus is that it is using both senses to locate its prey; also the beak is very sensitive and can pick up vibrations made by the worm’s movements. It is best not to tidy leaf litter too much, or too early, as it will be sheltering insects which Blackbirds will root for, throwing the leaves aside to find them.
Their breeding season starts in early March and will continue until July during which 2 or 3 clutches will be laid. Nests are built by the females in hedges or shrubs and occasionally in an outbuilding and, although she will be the one to incubate the eggs and brood the young, the male will help with the feeding. The song of the male Blackbird is a joy to hear. Mellow and melodious it can often be heard late into the evening fooling people into thinking they are hearing a Nightingale; the Robin is another bird that will sing at night.
November is the month when Grey seals are giving birth. Horsey and Blakeney are good places to see them but there have been reports of people being silly and trying to get too close. It is never fair to disturb wild animals, particularly at such a sensitive time, so stay well back and please don’t take your dog.
An update on our cathedral Peregrines. Both the original male and the new female are still visiting the nesting platform and both birds are busily tidying the nest scrape; this is territorial and bonding behaviour as it is too late in the year for eggs to be laid. If you have been looking at the web cam you can tell the difference between the birds as the female is ringed but the male is not; she also has a more speckled breast than he does. Fans have christened the male Norman and the female is known as GA because that is what is on her ring. If both survive the winter it looks as though they will pair up next spring. I wonder if the original female will be drawn back to the site to try to re-establish her rights.
Things to do this month include:
• Autumn towards Winter / Wildlife Wander / Bats – all at Cley Marshes.
• Hibernation Hibernaculum – Hickling Broad.
www.norfolkwildlifetrust.org.uk or 01603 625540.
• Beginners Birding – Titchwell Nature Reserve. 01485 210779.
© Sheila Sims 2016