Abundant winter visitor and localised breeder

Status in winter

Black-headed Gull is the most numerous of the gulls found in the region. It is an abundant winter visitor and comprises 70% to 80% of the gulls at most roost sites. At the huge Draycote Water roost in Warwickshire the figure is probably higher still. Accurate counts from Draycote are lacking during recent years, the sheer numbers discouraging observers from attempting a count. During the 1990s and early 2000s, estimates were of the order of 25000, with a highest count of 50000 in 2005, while the count from BTO's Wintering Gull Roost Survey in January 1993 was 38500. Although this was the second-highest count from an inland site, such numbers are well down on estimates from earlier years e.g. 80000 in 1977 and up to 100000 in 1973. Although there has  been a decline since the peak numbers of the early 1970s, it is probable that some more recent counts are  under-estimates to some extent. A subjective comparison of roost-size (area occupied) at Draycote with that at other sites (e.g. Blithfield and Chasewater in Staffordshire), where the number of birds is estimated in the order of 10000, would suggest that numbers at Draycote are substantially in excess of 25000.

Table 1 lists the five-yearly mean maximum counts from selected roosts. It should be noted that the 'mean' counts mask some wide variations in annual numbers (or estimates) and that , unfortunately, data are lacking from several other important sites.

Table 1. Five-yearly means of maximum counts of Black-headed Gulls at selected roost sites, 1986 - 2015.
(Numbers in brackets indicate figures based upon limited and perhaps unrepresentative data)

As well as traditional roosts at water-based sites such as reservoirs and lakes, there are instances of Black-headed Gulls roosting on rooftops. This is an under-studied phenomenon and data is currently very limited. As part of a survey for larger species within the perceived strike-hazard range of Birmingham Airport, Lee Johnson (in litt.) located 1000 Black-headed Gulls roosting on the roofs of the Jaguar Land-Rover works near Solihull in mid-August 2016. At least 600 roosted on a single roof during August 2021 (pers obs). Much of the rooftop space cannot be viewed from surrounding land and supplementary observations from different watch-points showed gulls arriving from several directions. Thus, the overall total arriving at the roost was probably again of the order of 1000 individuals. As far as is known, Black-headed Gulls do not breed on rooftops in England, though a few pairs do so in Scotland (Coulson 2019). It may be that Black-headed Gulls and additional LBBGs are attracted to a pre-existing roost involving Lesser Black-backed Gulls remaining from the breeding season? This roost disperses in mid-September, again perhaps 'triggered' by remaining local breeding LBBGs departing the site. However, some rooftop roost nationally persist through the winter and may peak at that time (Deacon 2019).

Changes in working practices at refuse tips and recent closures are inevitably affecting the numbers of gulls wintering inland, and a decline in numbers of most species is predictable (see Herring Gull and Lesser Black-backed Gull for more detailed discussion of this issue). However, while numbers roosting at Coton in N. Warks and some other sites have declined significantly, counts from other roost sites close to landfill sites still in operation (e.g. Chasewater) do not as yet indicate a decline in overall numbers of wintering Black-headed Gulls (see Table 1).

Ringing recoveries show that Black-headed Gulls wintering in the region originate from both British and continental colonies. Within the UK, recoveries have shown arrivals from Hampshire, Kent, Essex, Lincolnshire, Yorkshire, Durham, Cumbria, Northumberland, and Shetland (The New birds of the West Midlands, Harrrison & Harrison 2005). A majority of ringing recoveries in Britain as a whole, of gulls ringed in Europe, is from Fennoscandia, the Baltic states, the Netherlands and Denmark, with others from further east in Russia, Germany, Poland, Belarus and the Czech Republic (BTO's The Migration Atlas, 2002).  The Birds of the West Midlands (Harrison et al. 1982) documents 96 recoveries from ten European countries (including the Baltic States), of which 21 (21.9%) were from Denmark, 19 (19.8%) from Holland, 14 (14.6%) from Finland, and 11 (11.5%) from Germany.

Age-distribution studies (Dean 2021) confirm that adults predominate among Black-headed Gulls wintering in the West Midlands. First-years comprise little more than 10% overall but in individual gatherings range between 4% and 30%, reflecting age-related habitat preferences and feeding regimes.

Breeding status

Black-headed Gulls have a long history of breeding in Staffordshire and a more recent presence in Warwickshire and Worcestershire (for details see Harrison et al., 1982, The Birds of the West Midlands, and Harrison & Harrison, 2005, The New Birds of the West Midlands). In Staffordshire, around a dozen pairs continued to breed at Aqualate up to 2005 but thereafter numbers declined and in 2010 no breeding occurred. In 2007 nesting activity was recorded at the nearby Coley Brook Marsh. However, the principal breeding areas are now based on the sand-and-gravel workings in the Tame/Trent Valley system of southern Staffordshire and north Warwickshire. As many as 123 pairs nested at Elford (Staffs) in 1987 but this had declined to 52 pairs by 1990. At the nearby Barton pits 100 young were counted in 1994.Three pairs bred at Kingsbury Water Park (Warks) in 1982 and by 2005 150 pairs bred at Kingsbury and 231 pulli were ringed. Breeding in this area has expanded to 250 pairs by 2015. The largest breeding colony in the region is now at the adjoining Middleton Lakes RSPB reserve (Staffs / Warks), where there were 825 nests in 2015. By 2019, a regional total in excess of 2500 pairs is indicated by data presented in WMBC Annual Report No. 86, including 350 pairs at Belvide (Staffs), about 400 nests at Marsh Lane (WMids), 449 pairs at Upton Warren (Worcs) and 216 pairs and 696 pairs noted for Warks and Staffs, respectively, at Middleton Lakes.

Harrison & Harrison (2005) wrote that ringing has shown nestlings from colonies in the region disperse widely across the UK during the first few months after fledging, with recoveries from Dorset, Cornwall and many Welsh counties.

HPAI

Black-headed Gulls have been among the species most severely affected by Highly Pathogenic Avian Flu (HPAI), colloquially referred to as 'bird flu'. One of the sites most impacted nationally has been Marsh Lane, in the West Midlands. Here, the hitherto flourishing colony had increased  from 635 nests in 2021 to 830 nests in 2022. However, in 2023, although good numbers of pairs were present at the onset of the breeding season, around 1000 individuals were estimated subsequently to have died from HPAI  (see https://www.bto.org/community/news/202305-wave-avian-influenza-hitting-black-headed-gulls). The impact of HPAI on local and national populations, and even arrivals of migrants from overseas, will become clear in the next few years.