Wild Things columnist Eric Brown samples Waxwing fever and advises readers to look out for these beautiful multi-coloured birds while participating in the 45th annual RSPB Big Garden Birdwatch.

Continuing the Christmas theme, here's a riddle fit for any cracker: what's pink, white, red, grey, yellow and black and makes people go "wow" ?

The picture is a bit of a giveaway isn't it ? It's the waxwing, one of Britain's most beautiful birds. Every few years they desert their native Scandinavia not because of icy temperatures which slid to minus 22c in Helsinki over the holiday. But if the berry crop fails there they often head towards Britain which offers abundant fruit and milder days.

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When this happens it is known as a "waxwing winter" here with birds first arriving in Scotland around October then slowly filtering south in pursuit of life-sustaining berries. They are often seen on berry-bearing shrubs around supermarkets or in housing estates and congregate in flocks of up to 50.

Waxwings located one important food source in St Paul's Cray, Orpington, where they ignored traffic on the busy Sevenoaks Way to descend on a berry-laden tree in a new year treat for birdwatchers.

When I first saw them on January 4 there were 16 scoffing white berries almost completely unfazed by traffic and people walking by. I returned for another look six days later and the number had swollen to 38 whirling around like a plague of insects. Plenty of wow factor and truly breathtaking.

When the berries ran out in St Mary's Close the waxwings relocated to Warren Road, Orpington.  Waxwings have been reported all over south London and the home counties so keep an eye open for them if participating in the 2024 RSPB BIg Garden Birdwatch this weekend.

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Tall trees and a good supply of berries will lure them in but if you don't have those in your garden you can nominate a local park to conduct your survey. The RSPB hope more than half a million people will take part in the 45th annual watch. If you haven't participated before, just record the birds visiting your garden, park or chosen open space during a single hour over the weekend (January 26 to 28) and then submit results to the RSPB.

You can do it while sipping a coffee and looking through the patio window. Put some bird food out beforehand and increase your species count. Results will be compared with previous years and give the RSPB some idea how birds are faring.

You may not see a waxwing but your results will contribute hugely to this important citizen science project.

Register and submit results by February 18 at www.rspb.org.uk/birdwatch using code BH21.