We are currently experiencing a nocturnal invasion of vast proportions. After dark, thousands of winged visitors are passing overhead, and if we venture outside, we can hear the irrefutable evidence of their night-time movements. It is one of the most intriguing wildlife spectacles that Yorkshire has to offer.
The sounds that break the stillness of the night emanate from a range of bird species that have navigated their way to our shores to spend the winter here. Two of the most frequently- heard voices belong to birds that have nested elsewhere in Europe and in northern Russia: the redwing and the fieldfare, both members of the thrush family.
I remember the first time I heard the thin, high-pitched calls of a group of redwings as they passed over my suburban garden. How could they find their way in the dark over miles of countryside? Would they continue flying till dawn? How much further south would they travel in their search for a milder climate? The workings of the natural world generate so many intriguing questions, many of them still yet to be answered by scientists.
Much more striking are the staccato vocalizations of fieldfares, a larger cousin of the redwing, which are heard less frequently on their nocturnal migrations. It is incredible to think that these thrushes have successfully traversed the North Sea on their way to Yorkshire, without stopping to catch their breath or to refuel.
During daylight hours it is possible to enjoy the distinctive feather detail of the redwing and fieldfare, as recently-arrived birds eagerly devour their favourite food at this time of year – hedgerow berries. Wharfedale is currently alive with thrushes doing precisely that, making it an ideal time to get to know these two species.
The redwing is the smallest thrush seen regularly in Britain. Patterned superficially like a song thrush, its most obvious features are a creamy eye-stripe and the rusty flank and underwing area which gives the species its name. They are quite confiding and allow close approach as they gorge themselves on berries.
Significantly larger in size is the fieldfare, with its distinctive grey, black and chestnut upperparts and speckled chest. It is a bird that is easily spooked and likes to keep its distance from people.
You can tempt these winter visitors to your garden by scattering old apples on the ground, and it is not uncommon to also find them teasing invertebrates out of the soil.