The seagull population during the time of humans was much greater than nature could support. Most seagulls depended on human refuse and without humans around seagulls faced a huge die-off. With the last of mankind's food and refuse gone the seagull's numbers will dwindle but they are most likely to survive. Like the rats, seagulls will have to return to getting their own food. However they can still eat insects, remains of plants that got eaten and carcasses of dead animals so they will survive.
By 150 years after people, seagulls had made a comeback due to returning fish populations in the ocean. Although the seagulls have survived their numbers are much small when compared to the numbers their ancestors once had.