North Wales Urban Gull Survey

Herring Gull. Beth Arkwright

Participate in a one-off survey of urban Gulls in North Wales this spring.

The distributions of Herring Gulls and Lesser Black-backed Gulls, in particular, have changed substantially over the last 50 years, and increasing numbers now breed on rooftops in urban areas, sometimes far inland. Many of these birds may feed exclusively in terrestrial habitats, whilst others nest in towns and cities but make more ‘traditional’ foraging trips out to sea.

The urban gull pilot study in North Wales is the second phase of a two year project being undertaken in support of the national seabird census, ‘Seabirds Count’. The aim of the project is to quantify the underestimation resulting from ground level surveys, and to assess whether correction factors can be calculated to enable robust breeding population estimates for urban gulls to be generated from ground level surveys.

In order to do this, counts from ground-level surveys of 1-km squares carried out by volunteers will be compared to counts of the same survey squares produced from digital aerial surveys. Based on previous experience, we know that observers surveying from ground level will be unable to detect a proportion of the birds nesting on rooftops and that the proportion hidden from view will vary across survey squares. The objective of this project is therefore to quantify average detection rates and the variability in detection probability across survey squares.

Time / skill required

  • We expect that between one and three hours survey work will be required.
  • Identify and distinguish between Herring Gull and Lesser Black-backed Gull, identify nests and territories.

Project timeline, contributions & findings

Project timeline

One survey visit in May 2019.

Contributions & findings

Results will contribute to the National Seabird Census ‘Seabirds Count’.

The surveys in North Wales follow the first phase of this pilot study which was carried out in Birmingham in 2018. A summary of the Birmingham survey is available -  BTO Urban Gull Survey 2018 Summary for volunteers (PDF, 1.03 MB).

It is anticipated that the results from the survey will inform future population estimates from surveys of urban gulls carried out as part of Seabirds Count.

What is required?

We are looking for volunteers to help with this survey in May 2019. Only one survey visit is required to each square, so we would welcome participation from observers who are visiting the North Wales area during May as well as from those who are resident in or close to the survey area.

Each square should be covered from ground level and therefore access to vantage points on high buildings is not required for this survey.

Where are the survey squares?

Survey squares are located along or near the North Wales coast between Llandudno and Holywell in north-east Wales as well as in the Connah’s Quay and Wrexham areas. A map of the survey squares is shown below (all coloured squares require surveying with the different colours representing different urban habitats from mostly suburban to mostly industrial).

North Wales Gull Survey map - all squares.

Skills and time required

Each survey site is a 1-km square. The survey duration depends on the amount of urban habitat in the 1-km square, but in most survey squares, we expect that between one and three hours survey work will be required. A good level of fitness may be required to walk round squares which have a substantial extent of urban habitat. Surveyors need to be able to identify and distinguish between the two main target species: Herring Gull and Lesser Black-backed Gull, and record the numbers of individuals, apparent territories and nests observed in the square.

Further information

For more information on taking part, please contact the survey organiser, Ian Woodward (ian.woodward [at]


We would like to thank all volunteers who took part in the first phase of the survey in Birmingham in 2018. This project is being carried out on behalf of the Department of Food and Rural Affairs (Defra), with involvement from Natural Resources Wales and Natural England, and it is expected that the survey results will inform urban gull population estimates for Seabirds Count, which is being co-ordinated by the JNCC (Joint Nature Conservation Committee).

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