Aerial surveys are only a component of the winter survey programme because in some cases, aerial survey methods may miss some species, e.g. species that avoid aircraft, or species that are close inshore and are missed by observers while the aircraft is banking at the coastline. Shore-based counts can potentially collect data on some species that might be missed by aerial surveys, although the offshore extent of such counts can be limited. Boat-based surveys can potentially collect data on some species that might be missed by aerial surveys, while retaining the ability to survey the offshore extent of aggregations. In addition to aerial surveys, the JNCC winter survey programme included shore-based counts of inshore waterbirds within the upper Firth of Clyde, selected areas of the Outer Hebrides, and the inshore waters north of Orkney Mainland. These counts collected additional data on the numbers and distribution of inshore waterbirds and attempted to count the total numbers of birds present within the survey areas. Several boat surveys were also conducted around Shetland by an external contractor to collect additional data on the numbers and distribution of great northern divers and Slavonian grebes in the area.
Only the aerial surveys conducted by JNCC in Scottish waters are considered in this report. This report outlines the methods used during the 2007/08 winter aerial surveys and presents the recorded numbers and distributions of the species observed in each survey area.