HUNDREDS of Andover people are expected to take part in RSPB’s Big Garden Birdwatch which takes place over the weekend of 24 and 25 January.

It is the world’s biggest wildlife survey and last year, more than 16,140 Hampshire residents joined half a million people across the UK, spotting the birds in their garden to reveal which species are doing well and which are struggling.

Last year’s results put blue tits as Hampshire’s most common garden bird, followed by blackbirds and house sparrows.

Hester Phillips, of the RSPB South East, said: “The survey started 30-years-ago as a winter activity for our youth members.

“Now it appeals to both children and adults because it’s fun, easy and only takes an hour to join in.

“Reaching our 30th birthday is a huge achievement and shows just how passionate people in Hampshire are about birds and wildlife.

“Over the last 30 years we’ve clocked up more than three million Big Garden Birdwatch hours in the UK, which is just incredible.”

Last year, Hampshire participants recorded an average of two house sparrows per garden, making it the third most common garden bird in the county.

In 1991 the species was the most common garden bird, with an average of nine sparrows per garden. This echoes the national trend, which has seen sparrows decline by around two-thirds over the survey’s 30-year period.

Because of what the RSPB has learnt from the Big Garden Birdwatch, several studies are under way to identify how struggling species can be helped to recover.

The findings of BGBW 2009 will be published at the end of March.

To take part in Big Garden Birdwatch visit rspb.org.uk/birdwatch or call 0300 456 8330