The RSPB Red List prioritises action for species that need help immediately. Criteria include:
Species is globally threatened.
Historical population decline in UK during 1800–1995.
Severe (at least 50%) decline in UK breeding population over last 25 years, or longer-term period (the entire period used for assessments since the first BoCC review, starting in 1969).
Severe (at least 50%) contraction of UK breeding range over last 25 years, or the longer-term period.
"Prioritising is vital as we don’t have money and resources to work on everything, even within the red list we can’t prioritise action for all 67 species."