Magpies eat other birds' eggs, and it had been speculated that this had led to a recent major decline in songbird numbers. However the Telegraph reports that a recent study lets them off the hook. It seems that there is a correlation between Magpie and songbird numbers, but not a significant causality – at least not in the direction that people feared. So if numbers of songbirds decline then Magpies may decline also because there are less eggs to eat, but Magpies are not increasing in numbers to the detriment of songbirds – their numbers rise and fall in parallel.