Get the pot reference i reckon. The date, that time of day, in the afternoon. Because i live close to the sea, an image is evoked of the harbor (big ass commercial waterfront really, but you can find secluded spots by the actual docks) I get the feeling of smoking a joint on the docks with a few friends, just staring at the boats and the water. Everybody wants the last drag. Maybe it feels like a race, we're all afraid there is not enough. Maybe we laugh, maybe somebody argues. We have to stay secluded because it is illegal, therefore slightly trapped. Gulls flying overhead. Maybe circling the lighthouse or so, swooping down for food, scavenging. The gulls in the Cape are aggressive birds, they will snatch fries from your hand if you sit outside at one of the diners.

Gulls can be a metaphor for other people, outsiders to the group, those who do not understand, who scavenge for money or wear suits or police uniforms or whatever.  

^^that is just the image it illustrates, in my head, with my frame of reference. But i get the idea that it is mainly metaphorical. The gulls in it are dark. 

I liked Mynel's interpretation too.