The big garden weigh-in
We're sure that many of you have taken part in surveys to count the numbers of birds in your garden, but numbers only give us one picture.
What the BTO (British Trust for Ornithology) is keen to know is just how much bird life our gardens support - a 'biomass score' for each garden.
Mike Toms, BTO Head of Garden Ecology:
"We need a sensible measure by which we can compare gardens of different types and sizes of bird visiting."
In terms of 'bird biomass' 80 goldcrests = 1 wood pigeon
Large birds like wood pigeons will consume huge amounts more from your feeders than a house sparrow for instance, so mass is as important as numbers.
From tonight and for the next 5 days you are invited to make a simple count of the birds that use your garden. And this is how you do it...
Step 1: Download the recording form, find a comfortable chair, a pair of binoculars if you need them and a bird identification book
Step 2: Check the clock, and for the next hour keep a close eye on your garden.
Step 3: Record the maximum amount of birds of each species that you see in your garden at any one time during the hour.
Step 4: Submit your results online and see your biomass score straight away.