October is the month when late-staying summer visitors such as swallows and house martins, shortly heading off for Africa, overlap with early winter visitors like redwings and fieldfares from Scandinavia. These winter thrushes feed voraciously on hawthorn berries when they arrive and may be joined by blackbirds, and song and mistle thrushes, as well as the occasional late ring ouzel. It is always worth looking carefully at berry-laden trees in autumn and winter. Mistle thrushes may occupy a single berry-laden bush and defend it against all other birds. In some winters when the berry crop fails or is poor in Scandinavia, large numbers of waxwings will ‘invade’ the east coast and small numbers of them may reach the south west.
Another sight to savour in late autumn are the flocks of golden plovers flying around and settling on the moor; Sharpitor and Cox Tor are both reliable areas to watch out for these golden-brown wader flocks, sometimes numbering several hundred. In some cold winters there may be several thousand birds using the moor. A few pairs of golden plover used to breed on Dartmoor, but they last bred in 2004, perhaps due to changing habitat (or climate change?).
An unobtrusive woodland bird, the jay, which is chestnut-coloured with a white rump and brilliant blue ‘shoulder’ patch (or alula), is more often heard than seen. However, the autumn is a crucial time for jays, which depend heavily on acorns for winter food. As many as 3000 acorns can be collected and buried by a single jay, and studies have shown that the jay retrieves around half of all the buried acorns. This gathering of acorns is so important to jays that in years when the acorn crop fails, parties of jays may move large distances in search of acorns.
Very little birdsong is heard in autumn. From August onwards robins sing their ‘wistful’ and ‘laid-back’ autumn song, very different to their much more vigorous spring song. Though different in nature, both songs proclaim the robin’s territory as robins are one of the few British birds that are territorial throughout the year. A few woodpigeons and collared doves continue to sing occasionally (one is singing as I write), and both may well still have young in the nest until October or even November.
For those interested in insects, autumn can be an exciting time, with migrant butterflies, moths and dragonflies turning up every year. Just like many autumn leaves, so glorious with their rich display of colours, some of these autumnal insects have beautiful golden-yellow, chestnut or reddish-brown wings – moths with names such as the Canary-shouldered thorn, Pink-barred sallow, Chestnut and the Red-line quaker.
By October hedgehogs should have accumulated sufficient fat reserves (they should weigh at least 1 pound, or 450 grams) to enable them to survive the winter. They build winter nests, typically on the ground and mostly made of leaves, in preparation for hibernation. During hibernation their body temperature drops from 35 degrees centigrade to 10 degrees or less, and their heart rate slows to 20 beats per minute or less. This is to conserve energy during the coldest months of the year. If the weather remains mild into November and even December, hedgehogs will remain active until cold weather sets in. Gardeners should be aware that hedgehogs may choose the bottom of a large bonfire as a suitable site for hibernation, so please check carefully before setting it alight.