Monday, 24 February 2014

Urban Gulls

Sarah and I spent a family weekend in the spa town of Cheltenham on the edge of the Cotwolds in Gloucestershire. Cheltenham is a fantastic town and one of most conspicuous residents are the Herring Gulls and Lesser Black-backed Gulls that nest on the roof tops. At the time of our visit the gulls were just settling back to their roof top nest sites and there was a great deal of long-calling and squabbling as territories are established and pair bonds formed or reignited.

Lesser Black-backed Gull (Simon Colenutt)

The colonisation by nesting gulls of our towns and cities is a relatively recent phenomenon. During the 1930’s onwards populations of gulls increased as a result of many factors but was primarily related to an increase in food supplies and, in the 1950’s, when changes in The Clean Air Act 1956 meant a change in landfill practices resulting in the covering rather than burning of waste resulting in the creation of an abundant food source. Gulls were able to respond to this increase in food availability and populations rapidly increased. Colonies on the coast were quickly outgrown and colonisation of urban areas began. By the early 1970’s urban nesting gulls were a national phenomenon and towns and cities now support populations of urban gulls ranging from a few pairs to colonies of national significance. Cities offer gulls, amongst other things, a ready supply of food, safety from predators and limitless nesting sites and as a result breeding performance is often higher than at more traditional colonies which has resulted in disparity between the performance of colonies with urban ones increasing while traditional colonies are declining.