Shelducks occurred on relatively few CBC plots, most of which were close to a coast or an estuary, and it is unclear how well the CBC trend represented the UK breeding population. The CBC showed a substantial increase from the mid 1960s until the early 1980s, some decrease during the 1980s, and stability during the 1990s, although the wide confidence intervals provide scope for other interpretations. Population increase was associated with expansion of range, measured as an additional 20% of occupied 10-km squares in Britain between 1968-72 and 1988-91 (Gibbons et al. 1993). The UK winter Shelduck population rose during the 1960s and 1970s, alongside the rise in breeding numbers, but then decreased from the mid 1990s, although a slight upturn has occurred in the last five years (WeBS: Frost et al. 2020). The BBS index is affected by occasional large counts, and therefore its confidence intervals are again relatively wide. BBS results show no clear population trend since 1994, but there has been further expansion of breeding population (Balmer et al. 2013). The species has increased across Europe since 1991 (PECBMS: PECBMS 2020a>).

The continued colonisation of inland breeding sites since the 1968–72 Breeding Atlas is the most striking change for the Shelduck and is also consistent with the change in range that has taken place in winter; increases of 34% and 17% in range size were recorded when compared with the 1968–72 Breeding Atlas and the 1981–84 Winter Atlas respectively.

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

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

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

Shelducks are present throughout the year, though more often reported in winter and during spring migration.

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.