Do you have plans this weekend? If you have an hour to spare, then why not take part in the RSPB's Big Garden Birdwatch. All you need to do is to count the birds that visit your garden in one hour. You can do it at any time this Saturday or Sunday (30th and 31st January 2010).
The RSPB have been running this survey for 30 years now, and every year people like you submit their results to the RSPB website. Everybody putting in just an hour on one weekend adds up to around 6 million birds being spotted each year. This helps the RSPB to see if some bird species are less common than they used to be, and knowing that some species are struggling and declining in numbers is the first step in being able to protect them.
And the best bit about it? You can do it from the comfort of your own home. You can settle down in the armchair with a cup of tea and watch the birds - no wet weather gear, warm clothes or expensive bird watching equipment is needed. Just download the ID chart from the Big Garden Birdwatch website to help you identify the birds you see.
The key thing is to record the highest number of each species you see at any one time. This stops you from overestimating, e.g. over the course of an hour if you see 5 blackbirds, but each time they're always on their own, you dont know if that was 5 different birds, or the same one coming back 5 times. In this case you would record 1 blackbird. All the instructions are on the Big Garden Birdwatch website anyway.
So get the kettle on, and get counting!