NATURE NOTES - Written by Dr Martyn Stenning
December 2023 Nature Notes
At 7 pm on 10th November, the temperature outside was 6.60 Celsius. It was pitch dark since before 5pm. Next morning it was 20 C. at 08:00 h. Frost decorated both garden and car. In New Zealand, folk were experiencing daytime temperatures of c. 230 Celsius. Their days are lengthening and warming and ours shortening and cooling as the globe tilts them further south towards the sun. Winter is surely upon us. Also, we are experiencing low pressure fronts swinging in from the Atlantic Ocean across these islands and giving us a frequent drenching. All this affects the living natural world in many ways. Humans are part of this, and many homes have been flooded already in parts of these islands. Homes of animals will have flooded too. Hibernating hedgehogs and lizards will have been disturbed. Many invertebrates will have drowned and be washed away as they hibernate for winter. Most birds will have been able to fly to dryer areas, but will desperately look for food in new places to keep their tiny bodies warm through metabolic heat generation.
Fundamentally, there are 2 types of animals when it comes to keeping warm. These are 1. Endothermic animals like us and most other mammals, who keep their bodies warm by eating and ‘burning’ calories to maintain body temperature as we do at c. 36.80 Celsius. The body temperature of other endothermic animals may be different, for example, many birds maintain a temperature of around 400 C. The other type are 2. the poikilothermic (or exothermic) animals, whose body temperature is regulated by the external temperature. These are the invertebrates and primitive vertebrates such as fish, amphibians and most reptiles.
Animals that hibernate allow their body temperature to drop and fall into a kind of sleep, more accurately described as suspended animation, this includes some mammals such as dormice (dormir, French for to sleep). There are many dormice within the countryside around Uckfield. I used to monitor them in Lake Wood for many years. Even when they are sleeping, they sometimes squeak if they are disturbed, and can also be herd to snore on occasion. I know of no birds that hibernate, these little feathered animals must find extra food to keep them warm in winter. That is where we can assist by providing feeders and water in our gardens.
Dr Martyn Stenning
Nature Notes November 2023
No focus on climate change facts today, just a bit of natural history observation. Autumn is running late this year as we enjoy calm conditions and temperatures in the mid 20’s during the 1st 3rd of October. However, days are getting noticeably shorter as the Northern hemisphere of planet Earth spins away from the sun towards the shortest day solstice on December 22nd at 03:27 h. life adapts with migration and hibernation.
I went walking on the South Downs yesterday. It was a beautiful day with sheep grazing peacefully and Sussex Red cattle mostly lying down chewing the cud. There were flocks of several dozen skylarks hovering and calling to each other and generally ‘larking about’ with the joy of a warm bright day. Similarly, there were even larger flocks of meadow pipits doing similar things making their characteristic seep calls as they bounced around on the wing like a flock of very large gnats. Other notable birds were a red kite being mobbed by a carrion crow, and also a kestrel hovering statically as it watched for a vole or some other prey.
There is a dew pond near Ditchling Beacon, probably built hundreds of years ago by the shepherds of old, to maintain a supply of drinking water on the top of the chalk South Downs. Because chalk is porous, surface water is rare on chalk hills. However, for thousands of years, Sussex shepherds have grazed sheep up there. So, to provide water for humans and animals, the people dug these bowls, often in a natural depression in the chalk, with a diameter ranging from 15 to 30 metres. They lined the ponds with chalk ground down with the hooves of oxen that pulled a wide wheeled cart to smooth out the lumps. They often lined the pond base with Weald clay, and soot to deter earthworms from burrowing though and causing leaks, and straw to prevent the lining from cracking under the sun before the pond filled with water. Any moisture in the atmosphere would then fall in, or condense on the pond to eventually fill it. This should provide constant fresh water for a large community of animals and plants. I have even found rare and unusual fairy shrimps in the above mentioned dew pond, these are one of the most unusual species of animal known. They actually love living in ponds polluted with animal excrement and have the ability to live almost forever!
Dr Martyn Stenning