Explanatory notes for Thames Valley gull flightline map and ringing recovery map
15 December 2005 | Paul Cropper
Note that these maps do not comprise an official DEFRA report. They are intended to provide an overview of gull behaviour around the valley. Some features of the maps are now out of date, in particular several of the landfill sites have closed since 2003, when the work was done. Please note that these documents are all copyright of the Central Science Laboratory.
Gull flightline Map
- The movements shown all took place in the late afternoon/evening; flightline counts began no earlier than 14:30.
- The flightlines were all counted between September 1st 2003 and March 31st 2004. Because different counts were taken on different dates, there is inevitably some inconsistency in numbers. However the aim was to obtain the highest figure for each flightline.
- Some flightlines are shown without gull numbers where no accurate count was possible.
- Dotted lines indicate probable connecting flightlines.
- Counts were taken at the landfills every month; the "maximum gull count" shows the highest count recorded over the winter of 2003-2004.
- This is not intended as a comprehensive map of all flightlines. Since gulls can be very 'fickle' and vary their roosting site from one night to the next, there will always be limitations to the usefulness of a map of this kind.
- The reservoir roosts shown in the centre of the map are, from northwest to southeast: Queen Mother Reservoir, Wraysbury Reservoir, King George VI and Staines Reservoirs, Queen Mary Reservoir, Queen Elizabeth II Reservoir and Island Barnes Reservoir.
Ringing Recovery Map
- The map only shows recoveries from landfills. Recoveries from other types of sites (e.g. reservoirs, playing fields) are not included.
- "Recoveries" refers to colour ring inscriptions read in the field.
- The figures include recoveries of all species of gulls from both ringing sessions (12th/13th November 2003 and 20th/21st January 2004) sighted between 13th November 2003 and 31st May 2004.
- Visits to the landfill sites were of approximately 2 hours duration. The exceptions to this rule Hedgerley and Springfield landfills, where visits lasted up to 8 hours (probably resulting in an inflated number of ringing recoveries at these two sites).
- Counts of Yellow-legged Gulls are lumped with Herring Gulls, owing to the two species being considered conspecific at the time of the study.
© Paul Cropper, Central Science Laboratory, December 2005