Chris Chappell has some intriguing observations this month on moulting, preening and sunbathing.
Groups of swifts swoop around the villages and towns, feeding on insects to build up strength prior to their departure for Africa. They are one of the first migrants to leave. Swallows start to line up on the telegraph lines, twittering noisily. The fine spell in July has brought out plenty of butterflies and dragonflies, and the countryside is full of wild flowers and plants. However, the dry weather has caused some problems for wildlife, the hard ground making it hard for hedgehogs to feed, and the heat reducing the number insects for birds and bats to catch. Many bird species will start to moult at this time of year, and they skulk out of sight, as they are very vulnerable during this period. This is why you may get the impression in August that many birds have disappeared. The pale young birds will begin to gain the adult colours of the species, while adult birds renew their worn out feathers.
Many butterfly species peak at this time of year. Look out for red admiral, peacock, comma, whites and many more. As buddleia comes into flower, they attract butterflies in great numbers. It is a good idea to plant one in your garden for the insects that will feed on, and our beleaguered bees will take advantage. Dragonflies are also abundant now, too many to list, but look for damselflies and demoiselles along the rivers, and the large blue hawkers over ponds and lakes.
The Trust stages numerous events during August, led by experts in their respective fields, be it bats, butterflies or glow worms. Check events for availability, charges and advice re suitable clothing.
Sunbathing and preening
During the warm weather, you may see a blackbird or robin in your garden, wings outstretched in the sun, apparently sunbathing. There are various theories as to why birds do this, but the most popular explanation is the that the heat drives off some of the parasites that inhabit the host bird. It is also thought that the warmth helps the oils to be absorbed after preening. Most birds have a fat producing preen gland just under the tail (the parson's nose on a chicken or turkey) from which they gather oil in their beak, and then stroke it through the feathers. Each feather is carefully nibbled to realign the filaments. This is a vital process in the survival of the bird, as the oils help to keep out damp and cold, and condition the feathers for use in flight. Many species sunbathe, the crow family in particular. Most birds need to bathe, in water or dust, in order to clean and condition their plumage. Sparrows are particularly fond of dust bathing, fluffing up the feathers and flicking dust over their bodies. Afterwards they vigorously shake out the dust before preening. If you are able to provide a bird bath in your garden, this will help the birds maintain their condition, especially important in dry weather.
Interestingly, some birds such as pigeons, owls and hawks lack the oily gland, but instead have special preen feathers that disintegrate into dust, which is used to preen in the same way as oil. Jays and starlings have been observed preening on ant hills, it is thought that the ants secrete a formic acid as a defence mechanism which may be an aid to cleaning feathers, and removing parasites.
Ravens were relentlessly persecuted in the 19th century, due to their reputation for taking lambs and game birds. This unjustified slaughter, combined with the attentions of egg collectors, taxidermists and the pet trade, drove the population to extinction in many regions. Intelligent birds, they made very entertaining pets, Charles Dickens had two ravens. We live in more enlightened times, and the raven is now fully protected under the law, and populations have recovered. The raven is the largest member of the crow family, and now reasonably common in Somerset. The size of a buzzard, ravens can otherwise be distinguished from the smaller crows by the strong large bill, ruff on the neck, diamond shaped tail, agility in the air, and the call. The adults make a variety of noises, but you are most likely to hear a loud low cronk-cronk-cronk, sometimes more like a barking deer than a bird. Adult ravens can now be seen with three or four offspring in tow, the juveniles still dependent on their parents to find food. A family group may be watched performing aerial acrobatics over the Polden Hills, the Mendips or along the rocky coastlines. Ravens build a large nest at the top of a tall tree, or on a cliff face. Mating for life, and living for around 20 years, they stand apart from other crows. Their main source of food is carrion, but they will eat almost anything, including small birds or animals, and their eggs and young. In the breeding season they are subject to mobbing by rooks, crows and jackdaws, as they are rightly perceived as a threat if they get too close.
Photos by Chris Chappell
Large White on Buddleia
Six Spot Burnet Moth