The lifespan of seagull is affected by several factors, such availability of food and protection from predators as well as extreme weathers. Hence, it is but natural that seagulls living in captivity, such as in zoos, have longer lifespans compared to those living in the wild. But if young gulls in the wild survive the rigors of their first year, their chances of survival increase significantly and keep increasing with each passing year.
There is recorded evidence to show that a herring gull named Gull Dick visited the same neighborhood for 24 years. He used to visit Brenton's Reef lightship at Narragansett Bay every from from Oct. 12 to April 7 and during this visit the crew fed the bird boiled pork and fish.
Similarly, there are records of many gulls living longer than other members of their species.
Courtesy of ehow.com