Saturday May 4 was a day for rejoicing in the Brown household.

Battling through strong wind and driving rain, were two Swifts, the first to be seen from my house this summer.

The first appearance of these scimitar-shaped mostly black aerial masters always persuades me summer is finally here. Despite the atrocious weather. Each year Swifts leave Africa on 18,000-mile round-trip breeding migration flights to Britain.

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Someone once estimated that during their lifetime many Swifts fly the equivalent of several trips to the moon and back without touching down as they eat, sleep, drink and er reproduce on the wing. They are such accomplished flyers they can avoid bad weather here by nipping over to France or Germany and be back in time for tea!

Usually I’m lucky enough to see up to 10 Swifts from the window of my Sidcup house. This year so far the highest number I’ve had at one time is three. A reduction would match the national trend. Most bird books claim there are around 85,000 pairs summering in the UK but more up to date information reveals the population has crashed to around 50,000 pairs The most recent survey showed a 51per cent decline in breeding UK Swifts between 1995 and 2015. This is serious for our champion flyer.

An investigation is under way into the effects of chemical spraying on Swifts insect food while nest sites have been lost. House repairs eliminate gaps in brickwork and below roofs where Swifts nested. We can help here by putting up Swift nestboxes. Buy one at rspb.shop.co.uk. To make your own contact Swift Conservation. Also Swift bricks can be obtained online to fit existing houses or to be incorporated in new ones. Pester local construction companies in person or by letter to do this.

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Please report Swift sightings at swiftsurvey.org/rspb/home/index. Read “Swifts in a Tower” by David Lack.

I’ve just returned from a holiday in southern Spain where the air is thick daily with huge clouds of screaming Swifts. Wouldn’t it be wonderful if we could again see such a spectacle in the UK ?