Occasional, but increasing winter visitor.

Although Foster (1914) stated that they had been reported from Stevenage, prior to 1930 they were rarely seen in Hertfordshire. Their increase during the Twentieth Century has coincided with the growth of domestic refuse tips and sewage farms as the Human population has expanded.

At Stevenage they are usually seen flying over in small groups and, with birds increasingly seen at Fairlands Valley Lakes.

The largest numbers seen together are: 10 flying over Box Wood on 6 February 1966; 25 flying over Box Wood on 17 December 1972; 20 by the Hertford Road on 21 January 1974; 16 at Fairlands Valley on 26 September 1979; 11 at Fairlands Valley on 28 January 1980; 25 at Fairlands Valley on 7 February 1980; 35 Fairlands Valley Lakes on 14 February 2021.

The 2012 Winter Atlas confirmed their presence from five of the tetrads covering Stevenage.

Two birds seen at Fairlands Valley Lakes on 17 December 2022 had both been ringed at Pitsea Landfill Site, Essex. One ringed, GV37259 was ringed as a second-year bird on 2 April 2016, the other, ringed, GV15765 was also ringed as a second-year bird on 21 March 2015. GV37259 was seen again at Fairlands Valley Lakes on 24 January 2023.

2nd Winter Herring Gull, Fairlands Valley Lakes 28 September 2020