The Cormorant was almost exclusively a coastal breeder in the UK until 1981, but has since established colonies in many inland areas of eastern and central England (Rehfisch et al. 1999; Newson et al. 2006). Breeding had been recorded at 89 inland sites by 2012, and the inland population had risen to about 2,130 pairs by 2005 and 2,362 pairs in 2012 (Newson et al. 2007, 2013). Inland breeding in England is thought to have been sparked by birds of the continental race sinensis from the Netherlands and Denmark, although many nominate carbo from coastal colonies in Wales and England have contributed to its development.

Breeding numbers and productivity at sample colonies have been monitored annually since 1986 by JNCC's Seabird Monitoring Programme. This annual monitoring, which includes inland and coastal breeders, shows periods of temporary increase which have been followed by declines, and numbers are currently similar to those in 1986 (SMP: click here); these changes are accompanied by a long-term decrease in breeding productivity. There was a 10% increase in the UK population between full surveys in 1985-88 and 1998-2002 (JNCC 2015). Trends during 1986-2005 show decreases in Scotland and in northeast and southwest England, but no trend in Wales, and steep increases inland in England and in regions bordering the northern part of the Irish Sea (Mavor et al. 2008). The winter trend in Britain, comprising British and Irish breeders and continental visitors (Frederikson et al. 2018), showed strong increase from the late 1980s, and was stable between around 2002/03 and 2012/13 before increasing again (WeBS: Frost et al. 2020). Although the species is now green listed, both races that occur in the UK qualify for amber listing, for reasons unconnected with the UK trend.

During both winter and the breeding season there have been distribution gains, most often to low-lying inland areas.

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.

Cormorants are widely reported and present 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.

Relative frequency by habitat

The graph shows the habitats occupied in the breeding season, with the most utilised habitats shown at the top. Bars of similar size indicate the species is equally likely to be recorded in those habitats.