There are two species of gull, the Herring Gull and the Lesser Black-Backed Gull that commonly nest on rooftops in Bath and surrounding areas.
In Bath there is approximately twice the number of Lesser Black-Backed Gulls than Herring Gulls.
Both species can live for up to 30 years reaching breeding maturity at 3-4 years of age. Both species are omnivorous and are excellent scavengers.
Between 1995 and 2003 breeding pairs in Bath more than doubled to 458.
In 2001 a total population was estimated at 2,065, which includes immature birds and chicks.
Herring Gull
Herring gulls are large birds. They are about 55 cm (22") from bill to tail with a wingspan of about 85cm (34"). These birds are indigenous to the UK.
Eggs: 2-4
Incubation: 28-30 days
Fledging: 35-40 days
Length: 53-59cm
Wingspan: 78- 96cm
Weight: 690-1,495g
UK breeding: 161,000 pairs
Lesser Black-Backed Gull
The Lesser black-backed gulls are of a similar size, but are darker in colour. These birds are migratory.
Eggs: 3
Incubation: 24-27 days
Fledging: 30-40 days
Length: 52-64cm
Wingspan: 135-150cm
Weight: 620-1,000g
UK breeding: 85,000 pairs
Breeding pairs court and start nest-building from late April or early May onwards.
The nest is constructed from straw and grass, twigs, paper and any other material that the gull can conveniently use. The nest can be quite large and, if made of material accumulated over several years, very heavy.
Eggs are laid from early May onwards with two or three being the usual number. The eggs take about three weeks to hatch so the first chicks are generally seen about the beginning of June. Both species migrate to warmer climates in September.