According to this article Songbird Survival is planning an experimental cull of some larger predators such as magpies and crows in an effort to find out if they are responsible for wiping out songbirds. Songbirds have seen a dramatic decline over the past 50 years which some have linked to rising numbers of avian predators. Under the plan four areas will be set aside where the predators will be humanly culled. This will be compared with similar test areas where the population will be left unharmed and the two compared to see the results.
The RSPB says there is no evidence that crows and magpies are behind the decline, rather that is it other factors such as lack of nesting areas and lack of food in winter that are the blame. Personally I’m not sure a cull is the way to go, we have large numbers of crows, jays and magpies in our local area but also an abundance of songbirds. It will still be interesting to revisit this article to see the findings of the study.