Lesser Black-backed Gull Larus fuscus
Numerous winter visitor and passage migrant. Small breeding population in Birmingham and Worcester.
Lesser Black-backed Gull is a common winter visitor to the region and at most roosts it outnumbers the Herring Gull by a considerable margin. Numbers wintering in the region were very low prior to the late 1950s but then increased rapidly to reach a total of around 10000 by the late 1960s and 25000 - 30000 by the mid 1970s. 12000 were estimated in the roost at Draycote Water in December 1974. Numbers declined somewhat towards the end of that decade, with a total population of around 20000 (Harrison et al., 1982). Since then they have remained relatively stable, with Harrison & Harrison (2005) estimating the wintering population at the start of the current millenium as still around 20000. Counts at some of the larger roosts are now rather intermittent but data suggest a slight increase between 2000 and 2010.
The five-yearly mean maximum counts from selected sites during 1986 - 2010 are presented in Table 1.
|5-year Mean||Draycote||Tame Valley||Westwood||Belvide||Blithfield||Chasewater||Bartley|
|1986 - 1990||2400||695||1415||1175||2000||1950||380|
|1991 - 1995||2840||1645||2890||1135||1990||2860||1475|
|1996 - 2000||1400||800||2840||2325||1850||3120||1210|
|2001 - 2005||2075||730||4000||1950||2350||2400||1830|
|2006 - 2010||1875||1330||3600||4500||inadequate data||3740||inadequate data|
Table 1. Five-yearly mean maximum counts of Lesser Black-backed Gulls at selected sites in the West Midlands Region, 1986 - 2010.
Roosts of around 2000 have also been reported from Westport Lake in Staffordshire, while as many as 7000 have been estimated feeding at the landfill site at Throckmorton in Worcestershire.
The majority of Lesser Black-backs wintering in the region are of the race graellsii, which breeds in Britain and also in Iceland, the Faeroes, the Netherlands (where some intergrade with intermedius), Brittany, and Spain. Numbers begin to increase rapidly from September onwards and reach a peak in November or December. Numbers begin to decline during late January but the departure of wintering birds is offset by an influx of northwards-moving migrants during February and March, and it is not until late March or early April that numbers at (most) roosts become insignificant. Even during the summer, substantial numbers of predominantly immature birds can be found feeding at some refuse tips (e.g. 500 at Throckmorton during June 2003).
The monthly profiles of numbers from personal counts at two roost sites in the region are presented in Figure 1.
Figure 1. Mean monthly maximum counts of
Lesser Black-backed Gulls at two roosts in the West Midlands Region:
Bartley Reservoir, West Midlands, 1998 - 2003; Blithfield Reservoir, Staffordshire, 1980 - 1985.
Thus, in comparison with Herring Gull, the monthly profile increases significantly earlier, peaks a month or more earlier, and declines more slowly.
Very small numbers (generally single figures) of the race intermedius are reported each winter. This race breeds in southwest Scandinavia and Denmark, and migrates south and south-west to wintering grounds in western Europe and west Africa. Thus, it is to be expected in Britain and it is likely that it is significantly under-recorded in the West Midlands Region. There are a number of ringing recoveries of this form. However, identification of birds away from the breeding range is not straightforward, as there is some variation in the shade of grey of the upperparts in graellsii and very dark individuals can be found breeding in LBBG colonies in Britain. In Denmark and the Netherlands, may of the breeding birds are considered to be intermediate between graellsii and intermedius. There is some debate over the validity of intermedius as a subspecies rather than simply a cline among graellsii.
One or two birds of the nominate race fuscus ('Baltic Gull') have also been reported in most years. This race breeds in the Baltic area and northern Fennoscandia. It migrates south-east to winter predominantly in the Middle East and east Africa. Its numbers are declining. The identification of fuscus away from the breeding grounds is fraught with difficulties.
For a discussion of the status, movements and identification of 'Baltic Gull', a key reference is:
Jonsson, L. 1998. Baltic Lesser Black-backed Gull Larus fuscus fuscus - moult, ageing and identification. Birding World 11: 295 - 317.
However, a proviso re suspended moult in the other races must be kept in mind, even when consulting this reference.
The old perception that nominate fuscus could be identified on the basis of very black upperparts is now known to be false, as some individuals from the range of intermedius can appear just as dark in the field. It is structurally smaller and more elongated than intermedius, on average, but individual variation makes these characters unreliable. At one stage, and following Jonsson (op. cit.), the timing of the moult cycle seemed likely to provide a more reliable route to confident identification. The nominate race moults later than intermedius and graellsii and, prior to migration, adults normally moult only the two inner-most primaries. Thus, the outer primaries are still in place and all of uniform age, during August and September when the other two races are in active wing-moult. Unfortunately, it has recently been demonstrated that occasional individuals of intermedius (and graellsii) undergo 'suspended' moult, so that they too may show a moult cycle comparable to that of fuscus. Thus, positive identification of nominate fuscus remains problematic. It remains essential, however, to determine the precise state of moult with any suspected fuscus, as an individual in active wing-moult during the late-summer / early-autumn is certainly not fuscus.
For discussion of the more advanced wing and body moult of fuscus in its 2cy and the possibility thereby of confident identification of individuals of this age, see the relevant pages on the Gull Research Organsisation webpages at: http://www.israel.gull-research.org/02cyapril.html and the reference there there to the relevant paper on Primary moult of Baltic Gull during the first 15 months (in: Dutch Birding 28: 158-161) by Hannu Koskinen & Visa Rauste.
Ringing recoveries provide very little support for fuscus being other than a very rare visitor to Britain, though several colour-ringed fuscus have now been observed, as have individuals meeting the 2cy criteria mentioned above.
Given the difficulties in identification, it is considered that most claims of 'Baltic Gull' from the West Midlands Region will certainly prove inadequate and it is probable that none is sufficiently rigorous to prove acceptable. It is highly unlikely, for example, that many of the documentations submitted to county recorders include details of state-of-moult. In consequence, the reports claimed from the West Midlands Region are not itemised here.
The earliest breeding record of Lesser Black-backed Gull in the region involved two pairs which bred in Worcester in 1986. In the following year a pair bred in central Birmingham. By 1995, the number of pairs breeding in Worcester had increased to around 20 while at least 10 pairs were located in Birmingham (central and Hockley areas) during 1996. Since 1994 one to three pairs have also bred at Kidderminster, Bredons Hardwick and Stourport. In 2000, around 30 pairs were estimated in the Bromford / Tyburn area of Birmingham and 25 pairs at Worcester, while the species is thought also to have bred at Stratford. By 2005 there were still only nine pairs in central Birmingham, perhaps reflecting efforts to deter roof-top nesting there. In contrast, between 200 and 250 pairs were breeding in Worcester by 2005.
Thus, there is now a well-established breeding population in the region. Given the problems perceived as resulting from the larger breeding populations in south-west England (Peter Rock in litt.) the development of breeding in the West Midlands region has become the focus of attention. An investigation of the gulls nesting on roof-tops within the Birmingham boundary was conducted by Jim Winsper between 2008 and 2011and the results are presented in:
Roof-top nesting gulls within the Birmingham boundary
| Laughing |
Ring-billed | Common |
Lesser Black-backed |