From Opus

• The world's only poisonous birds are the Hooded Pitohui (Pitouhi spp.) and Ifrita (Ifrita kowaldi). These birds both have batrachotoxins in their skin and feathers (Batrachotoxins are the same poisons in poison dart frogs).
• There are still between six and seven million pairs of house sparrows in Britain. In the 1970s, there were 12 million pairs.