So, there's a seagull sargeant? No, that's a level of intelligence of which they're not capable... however, they're very observant and usually congregate in flcoks, both large and small. Those that are looking for food tend to circle fairly high above the ground and from there they can easily observe the actions of others in the flock. Finding food is easily determined by those looking for telling actions of other that have located it.
A lot of disagreement on the acuity of their sense of smell among ornithologists but, food especially relevant to seagulls, is most often thought to be found by sight.
Here in the U.S., our most common seagull is the Herring Seagull... white, of course, but with a yellow beak that has a red spot on the end of it... They most often (away from the seashore) gather at waste disposal sites and generally become a pest...
It's only the gulls that are near the sea that are called seagulls... whereas the ones by the bay are called bagels...