Breeding population size estimate for United Kingdom converted to specified units (breeding females) assuming a 1:1 ratio.

In the absence of a report from the Czech Republic for this taxon, surrogate data were provided by ČSO / BirdLife indicating a breeding population of 80–120 breeding females, with an unknown trend during 2001–2012 and an increasing trend (300%) during 1985–2012.

In the absence of a report from Greece for this taxon, surrogate data were provided by the Hellenic Ornithological Society (HOS), the BirdLife Partner in Greece, indicating a breeding population of 20–30 breeding females, with a stable trend during 2001–2012 and an unknown trend during 1980–2012.