The number of kingfishers in the Netherlands has doubled over the past year, mainly due to the mild winter, according to bird researchers Sovon.

In 2013, there were an estimated 370 kingfisher pairs. Last year, the number had grown to around 700. And with the mild winter, Sovon thinks this may rise to 1,000 pairs.

Kingfishers do not do well in cold weather. Their beaks can freeze shut leading to starvation and death.