Scarce winter visitor (and some decline since the 1980s)

Glaucous Gulls are regular winter visitors to the West Midlands Region and are anticipated every winter by gull-watchers at the larger roosts, particularly Belvide, Blithfield & Chasewater in Staffordshire and Draycote Water in Warwickshire. An early analysis of the status of Glaucous and Iceland Gull in the region was published in British Birds in 1976 (Dean and Dean, 1976).

A more comprehensive presentation follows. Factors such as the observation of gulls at (a) day-time feeding sites such as refuse tips, and (b) evening roost sites at lakes and reservoirs, inevitably introduce some duplication of sightings of individual gulls, and some adjustment for these factors  has been made in the analyses.  Also, as with all large gulls, there is a degree of uncertainty in age-diagnosis, which with 'white-winged gulls' affects 1W(juv) and 2W individuals in particular.

Annual distribution

The annual numbers of Glaucous Gulls during 1986 - 2015 (based upon arrival dates) are displayed in Figure 1.

Figure 1. Annual totals of Glaucous Gulls in the West Midlands Region, 1986 - 2015.

Numbers reached a peak of at least 41 during 1989 (and there were 40 during 1980) but, since 1990, there have been no more than 26 in any one year and generally fewer than 20. In 1996 only two individuals were recorded and only five during 2000 and 2003. Since then numbers have increased somewhat but this has been fitful (with 2014 and 2015 again poor) and the high numbers of the late 1980s have not been repeated.

Prior to the 1990s  Glaucous Gull was a considerably more numerous visitor than Iceland Gull. During the 1990s, however, there was a shift and Iceland Gull  became the commoner visitor. During the early 2000s, Iceland Gulls also declined and the totals of each species were more comparable. Both species then increased but Iceland Gulls distinctly more so, with unprecedented influxes of between 60 and 70 individuals during 2009 and 2012. In contrast, Glaucous Gull numbers declined again between 2011 and 2015. Additionally, adult Glaucous Gulls remain scarce compared with the levels prior to 1995.

During the five years 2011 to 2015, Iceland Gulls outnumbered Glaucous by a factor of over 3 to 1. The five-yearly totals for the two species between 1986 and 2015 are presented in Table 1. See also Iceland Gull for the comparative profile of annual totals of that species.

Table 1. Comparative five-yearly totals of Glaucous Gull and Iceland Gull, in the West Midlands Region, 1986 - 2015

Monthly distribution

The monthly distribution of records during 1986 - 2010 is presented in Figure 2.

Figure 2. Monthly distribution of arrival dates of Glaucous Gulls in the West Midlands Region, 1986 - 2010.

The majority of records falls in the period December to March (92%), with a clear peak during January (41%). An early analysis of the 65 records up to 1975 showed a rather later profile, with a peak in February.