A very friendly sparra - image courtesy of Mike LawrenceThe chatterring and squabbling of Cockney sparra's that has for so long been a feature of London's soundscape is falling silent.

The 2011 Big Garden Birdwatch results for London illustrate the birds' continuing decline. Comparing results from every borough with previous years findings, shows sparrows have tumbled down the tables; with fewer than ever before making it into the top three spots.

They are still dying and we don't know why. That alarms me and I'm surprised more people aren't scared. An interview on Radio 4's The Today Programme with Jim Naughtie treated the Big Garden Birdwatch as a bit of a laugh. Something that comes round with all too regular familiarity. I'm sorry he feels that way because behind the fun of taking part there is a serious message. Our environment and the wildlife it supports is changing.

The Big Garden Birdwatch is The Big Society in action. More than 600,000 people took part and if every one of them now stepped up their involvement with simple actions, such as planting wildflowers or allowing grass to grow long and set to seed, our environment would be richer and healthier. 

This is an over simplification of the situation, but if bird numbers are falling, it is likely they're struggling to find food. Which means that we've a shortage of either insects or seeds and berries in our environment. That in turn means we're heading for a lifeless concrete desert that will ultimately become a hostile environment for people too.

Thanks if you took part, look out for our Make Your Nature Count summer surveyThank you to everyone who reported for the Big Garden Birdwatch. In Greater London, the top three birds are starling, woodpigeon and blue tit (sparrows have dropped one place to fourth compared with 2010).

Sparrows didn't even make it into the top ten in Westminster, but are doing well in Islington and Southwark .. two boroughs working with our London House Sparrow Parks Project to try to solve the mystery of their decline. All of this work requires support from volunteers and funders.

We're working with local authorities, Transport for London, The Mayor's office, Northolt's Dawoodi Bohra Muslim Community and The Metropolitan Police to support London's nature. Even that formidable line-up is nothing compared with the efforts of individuals. 600,000 participants is great, but London has some seven million residents. Let's give Jim Naughtie something to really laugh about. Together, let's turn London into a thriving, vibrant garden city.