THE POPULATION STATUS OF
BIRDS IN THE UK.
Seven quantitative criteria were used to assess the
population status of each species and place it onto the red, amber or green list. These
criteria are listed below. The review excluded species that are not native to
the UK and those that occur irregularly as vagrants or scarce migrants.
- GLOBAL CONSERVATION
Species assessed as Globally Threatened were placed on
the red list.
- RECENT DECLINE
Species whose breeding or non-breeding population
declined, or range contracted, rapidly (by more than 50%) or moderately (by
between 25 and 49%) over the last 25 years were placed on the red and amber
- HISTORICAL DECLINE
Species whose populations declined severely between 1800
and 1995 were placed on the red list, except for those that have recovered
substantially (more than doubled) in the last 25 years, which were
amber-listed. In earlier assessments, all species showing a serious historical
decline were red-listed, but in this assessment the success of recent
conservation action has been recognised by moving recovering species to the
- EUROPEAN CONSERVATION
Species whose population status is unfavourable in Europe
(but which are not Globally Threatened) were placed on the amber list.
- RARE BREEDERS
Species with a mean population size of 1-300 pairs
breeding annually over the last five years were placed on the amber list. If a full census was carried out in a single year, the result of
this was used instead of a five-year mean.
- LOCALISED SPECIES
Species for which 50% or more of the breeding or
non-breeding population occurs at 10 or few sites were placed on the amber
list. This criterion
was used because a species whose population is confined to a few sites faces a
greater threat from chance events than one whose population is widespread. The
sites considered were either Important Bird Areas (identified by BirdLife
International) or Special Protection Areas (designated under the European
Unionís Directive on the Conservation of Wild Birds).
Species with 20% or more of their European population
breeding in the UK were placed on the amber list, as were
non-breeding wildfowl with 20% or more of their northwest European population
occurring in the UK and non-breeding waders with 20% or more of their East
Atlantic Flyway population occurring in the UK. This criterion is different
from the others as it is a measure of the UKís responsibility for each species
rather than the extent to which species are threatened.
- Red list species
are those that are Globally Threatened according to IUCN criteria; those
whose population or range has declined rapidly in recent years; and
those that have declined historically and not shown a substantial recent
- Amber list
species are those with an unfavourable conservation status in Europe,
those whose population or range has declined moderately in recent years;
those whose population has declined historically but made a substantial
recent recovery; rare breeders; and those with internationally important
or localised populations.
- Species that fulfil none of the criteria are green-listed.
The 1996 assessments helped to focus attention on a suite of
widespread but rapidly declining birds of farmed land, such as the
turtle dove, the skylark and the corn
bunting. It is generally accepted that these species have declined
because of agricultural intensification, and in the last few years a range of
schemes have been introduced to help them. All of the birds of farmed land that
were on the red list in the
earlier assessments are still there. In addition, another farmland bird, the
has joined them. Many red list species remain
relatively common in the countryside despite substantial declines.
WOODLAND AND URBAN BIRDS
Birds from two new groups appear on the red list: lowland woodland birds
and urban birds. The red-listed woodland birds are the lesser spotted
woodpecker, the marsh tit and the willow
tit, which have declined by 73%, 50% and
80% respectively over the last 25 years. A number of other woodland species have
entered the amber list. The urban species new to the red list are,
remarkably, the house sparrow and the
starling, both of which were formerly ubiquitous but have
declined by more than 60%. In contrast to the situation with farmland birds, we
do not know why these woodland and urban species have declined, and urgently
need to find out. As with farmland birds, some of these species remain quite
common despite severe declines.
Several species characteristic of Scotland, Wales or northern England,
such as the capercaillie and the black grouse, remain on the red list because
of continuing steep declines. Others, such as the corncrake and
the white-tailed eagle, are still red-listed although their numbers
are increasing due to successful conservation action. One upland bird, the
ring ouzel, is new to the red
Although the overall number of species on the red list has increased since
the last assessment (from 36 to 40), five species have moved from red to amber.
The populations of the red kite, marsh
harrier, osprey, merlin and
Dartford warbler have more than doubled in the last 25 years,
even though they had declined substantially previously. Much of the recent
increase in these species is due to the success of targeted conservation