From the BBC:
The success of a wild bird in Scotland despite declining numbers in the rest of Europe has mystified experts.
The rarer black-throated diver is also on the increase, possibly thanks to the anchoring of man-made rafts in lochs.
A survey of divers by the RSPB and Scottish Natural Heritage (SNH) found the two species had increased in the UK by 16 and 34% in the last 12 years.
Both have declined in Europe and the black-throated diver was last week made a conservation priority by the UK Government because of the declines elsewhere.
In Scotland, its numbers rose from 187 pairs in 1994 to 217 pairs in 2006. …
The RSPB said it was a mystery as to why red-throated divers have done so well.
Its numbers have risen from 935 to 1,255 breeding pairs in 12 years.