Vultures, tongue orchids: why are rare species here in UK?

The Egyptian birds are one of a number of foreign visitors, but why have these continental drifters fled north?

Boats have been chartered. Weekend arrangements cancelled. And hundreds of twitchers - whose aim is to see very rare birds in Britain - have been praying the latest arrival stays long enough for them to see it in the flesh.

The bird in question is an Egyptian vulture. This is the smallest member of its family in Europe, yet still sports a 1.7-metre wingspan, not much smaller than a golden eagle. The reason for all the excitement is because this is only the third Egyptian vulture ever seen in the wild in Britain; and, incredibly, the first since 1868. That one, found in Essex, was shot by a farm worker who saw a strange bird" amongst some geese.