As part of the work to identify possible SPAs
in the marine environment, JNCC has carried out new, targeted
surveys of marine birds. These surveys have
been conducted by JNCC staff, or by experienced contractors or
organisations on behalf of, or in collaboration with, JNCC. JNCC
uses a variety of analytical methods to assist in
deriving estimates of total numbers of birds from sample
survey counts and in mapping the distribution of these
birds.
Aerial survey
JNCC has carried out aerial surveys of inshore waters since the
winter of 2000/01 to collect up-to-date, detailed data on the
numbers and distribution of non-breeding aggregations of seaduck, divers and
grebes. These data are used to inform work in progressing
inshore
SPAs.
Boat survey
Since 1979, JNCC has conducted numerous surveys of seabird
and cetaceans at sea from ships using standard
methods, and this data is held in the European Seabirds At Sea
(ESAS) database. This database is currently being analysed to
assist in the identification of offshore aggregations of seabirds.
Coverage of UK waters by the ESAS database is extensive, but not
comprehensive, and the data has usually been collected at a coarse
resolution. Therefore, to inform specific aspects of the marine SPA
work, additional, targeted boat surveys are sometimes carried
out.
Land-based survey
JNCC uses existing land-based survey data, such as
Wetland Bird Survey (WeBS) counts
and county bird records, as well as the general
literature, to assist with assessing the importance of inshore
areas. In addition, targeted counts from shore have been
conducted around areas such as the Outer Hebrides, Wester Ross,
Inner Clyde and Orkney. These data are used to inform work in
progressing inshore SPAs.
Radio-tracking
JNCC has used radio-tracking of Manx shearwaters to assess how
far their evening rafting distributions extend offshore from their
breeding colonies. This was part of work investigating the
possible extension of existing seabird colony SPAs into
the marine environment. Radio-tracking has also been used to
supplement other survey data for red-throated divers to assess
which marine areas are important for breeding birds.