Once a symbol of London, the sparrow is these days a rare sight in parts of the inner city. The Royal Society for the Protection of Birds (RSPB) conducts an annual survey of house sparrow populations in London and wants your help with this year's count.
To take part, simply keep track of the number of house sparrows you see in a local park — or garden if you're lucky enough to have one — between 18 June and 12 July. Then fill in the RSPB's form here.
Our tip for spotting sparrows is to head along to ZSL London Zoo, which for some reason attracts the pluckiest avians we've ever encountered.
And, for the sake of inter-species balance, we should also point out that yesterday was Pigeon Appreciation Day. At least according to this attention-seeking pigeon.
Image by Luke Robinson in the Londonist Flickr pool.