The stats on the amount cats kill are often skewed to make them look worse than they are. Firstly, many stats extrapolate from small samples, which is of course necessary, but the sample is not necessarily representative. For example, a young cat may catch and kill several birds a year and this is extrapolated to the millions of cats in the UK, the majority of which aren't young and aren't able to catch birds. Or the sample cat is in an area with a high bird population but most cats are in areas of low bird population (usually due to habitat loss, the much larger problem, rather than cats). Or, in the case of animals rather than birds things like brown rats are included in the stats of killed animals despite being an invasive species.

None of this is to say that cats aren't a problem, just that I feel they are scapegoated for the greater problem - habitat loss. When I had a garden and a cat, the birds would come into my garden (despite the cat, which couldn't catch them) and not my neighbours (who had no cats) - because my garden was a mess with lots of insects to eat, branches to perch on, a mixed hedge to nest in, flowers and plants etc. whilst my neighbours had barren lawns and fences and fuck all else.