LBBG numbers on Skomer 1960-2012 (Source: Skomer Seabird Report)
Comparing this with the national trends we see that this is not a localised trend: The current UK estimate for Lesser Black-backed Gulls is 112,000 AONs It could be a case that the UK population is returning to more "normal" levels after an artificially high food availability (rubbish/fishery discards)
Trend in UK abundance index (solid line) of lesser black-backed gull 1986-2011 with 95% confidence limits (dotted lines).
Source: JNCC "Latest Population trends" http://jncc.defra.gov.uk/page-2886
Skomer has seen adult survival (number of adults returning year after year) reduce between 1993 and 2002 matching a decline in population - suggesting that the energy cost of reproduction is causing adults to not return to the colony. Skomer is the only location in the UK where adult survival rates are monitored so to what extent the changes in adult survival have effected the UK population as a whole is unknown.
Adult Survival of LBBGs on Skomer (Source: Skomer Seabird Report)
Lesser Black-backed Gulls are an interesting species and one which Skomer Island is providing a safe breeding habitat.
Thanks for all the volunteers (over all the years) who help with the Gull counts - without whom the task would be impossible.