Wild Things columnist Eric Brown samples waxwing fever and hopes readers looked 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" ?

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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. 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.

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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.

The RSPB Big Garden Birdwatch took place last weekend. Results will be compared with previous year's and give the RSPB some idea how all birds, not just the waxwing, are faring.