Reports of Sahara dust in late autumn are a signal to search for birds displaced from the desert and on to our shores

Some Novembers see southern Britain bathed in unseasonably warm sunshine, in that phenomenon known as an Indian summer. But few can match the events of early November 1984, when temperatures reached highs of 19°C, and balmy, southern breezes made it feel more like June than late autumn.

Then, on 9 November, car-drivers from Sussex to Yorkshire discovered their cars covered with a thin layer of fine, pale yellow dust. Amazing though it may seem, this really was sand blown here from the Sahara desert, more than 2,500km (1,500 miles) to the south.

What is an Indian summer? Read more

The next day, birders at Portland Bill in Dorset noticed a swift, always unusual at this time of year, as most swifts head south in August. Closer examination of this fast-flying bird identified it as a pallid swift, the paler, southern cousin of our own common swift.

This turned out to be the first in a quartet of pallid swifts, a bird so rare that only two had ever been recorded in Britain before this influx. Since then there has been an upsurge in records, mostly in October or November, when southerly breezes allow them to head north in a pioneering journey of exploration.

The pallid swifts weren’t the only North African arrivals that week: a desert wheatear, a suitably sandy coloured relative of our own northern wheatear, also turned up in Cornwall.

As a result, birders are now primed to look out for reports of Sahara dust in late autumn; a signal to search for birds displaced from the desert and on to our shores.