Breeding numbers are quite variable between years and not monitored annually by the BTO; trends are hard to assess except by intensive survey. There was a full UK survey in 1994 (935 pairs; Gibbons et al. 1997) and a repeat in 2006, by when the estimated UK breeding population had increased significantly by 34%, with stability in Shetland and Orkney but increase across the Hebrides and Scottish mainland (Dillon et al. 2009). Complete surveys of Shetland indicated a decrease of 36% there between 1983 and 1994 (Gomersall et al. 1984, Gibbons et al. 1997) and there was minor further decrease there by 2006 (Smith et al. 2009). The full surveys indicate that Shetland held 46% of the national total of breeding pairs in 1994 and 33% in 2006, though this decrease reflects the significant increases elsewhere in Scotland rather than the small decline in Shetland (Smith et al. 2009). JNCC's Seabird Monitoring Programme shows that breeding numbers at sample study areas in Shetland fluctuated without long-term change during 1980-2005, with low points in 1980, 2000 and 2004 (Mavor et al. 2008). Though previously amber listed through its 'depleted' status in Europe, the species was moved to the UK green list in 2015 (Eaton et al. 2015). Wintering numbers, mostly of birds from northern Europe, peaked in 2011/12 but have since decreased and are now similar to numbers in the early 1990s (WeBS: Frost et al. 2020).

Since the 1980s, there may have been some tendency for more pairs to hatch a second chick, although two-chick broods are only occasional in Orkney and changes in the distribution of nests recorded might have influenced the results. In 2011, however, there were fewer two-chick broods in Shetland than in any year since at least 1979 (Holling et al. 2013).

Red-throated Diver winter range has expanded by 32% since the 1981–84 Winter Atlas, with a large part of this being off northwest Scotland and parts of western Ireland. Some of this increase may be due to better coverage but some gains are likely to be real.

Bird Atlas distribution change maps show how bird distributions have change through time. Coloured upward-pointing triangles show places apparently colonised over the period; grey downward-pointing triangles show places apparently vacated. Shading shows squares occupied in all periods.

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

Red-throated Divers are recorded year-round

Weekly pattern of occurrence

The graph shows when the species is present in the UK, with taller bars indicating a higher likelihood of encountering the species in appropriate regions and habitats.