If you're out and about over the next few weeks, spend 15 minutes in a green area and tot up how many butterflies you see. Then give your results to the Big Butterfly Count and you've magically done your bit for conservation.
The country's general butterfly population is in decline (we now feel bad for not stopping the neighbour's cat eating a tortoiseshell yesterday) and doing a mass observation like this helps identify trends for different species. Butterflies can also be a bellwether for biodiversity changes.
It's very simple: spend 15 minutes in your garden, a park or a patch of overgrown wilderness when it's not raining and note how many individual butterflies you see (the same butterfly several times doesn't count, though we don't think that extends to keeping track of where each butterfly goes when it leaves your sight). You can download an identification guide and there are photos on the recording page to help you work out what you've seen, but don't worry if you haven't got a clue about the species. If you don't see anything, that's also very useful to submit.
The Big Butterfly Count runs 19 July-10 August, so get out there and get spotting.
Photo by Duncan Harris from the Londonist Flickr pool