Great black-backed gull (Larus marinus), Lesser black-backed gull (Larus fuscus) and Herring gull (Larus argentatus) are species of gulls that inhabit our towns and cities, often in large flocks. They take advantage of roofs of houses, office blocks, warehouses and factories for their nesting sites. Gulls will return to the same nesting spot year after year, they start breeding at 5 years old and can live for up to 25 years old. In April to May each year a female gull will lay around three eggs, with the incubation period being around 30 days. Gulls will often fly several miles to feed at landfill sites or from commercial waste.
Gulls can be aggressive during breeding season. There have been reports of gulls dive-bombing and attacking humans and pets, in a bid to protect their chicks. Their nesting materials and discarded food remnants can also cause problems with both domestic and commercial premises by blocking down pipes and causing flooding and contamination. Gull droppings (guano) contain a variety of bacteria and viruses that can cause ill health.