Last year, more than one million people recorded the birds in their garden, off their balcony, or in a park or field for an hour.
‘It’s important to find out what is happening to the populations of garden birds as we know in a lot of cases it’s declining and people want to find out why,’ said local RSPB committee member Ian Le Page.
‘Hopefully our statistics can help scientists figure out why this is happening and how to prevent it.’
The event is held at a similar time each year so the results can be compared and trends analysed.
‘All they need to do is count for an hour,’ Mr Le Page said.
‘You don’t necessarily need a garden, you can do it from a balcony or if you have no access to a green area, you could go to the corner of a park or field and see what you can count that way.’
An advantage of the event is how families can take part together and children can get involved, he said.
‘It gives them appreciation of nature, birds in particular.
‘I think it’s very important, especially with the situation of climate change, to bring youngsters in so they care about the environment and what’s going on around them.’
Mr Le Page recommended counting the number of species spotted rather than the number of birds, unless people were sure they were not counting the same individual bird multiple times.
The event runs from Friday until Sunday.
n More details and sign up forms are available on the RSPB website.