Seagulls are mentioned several times in the How to Train Your Dragon Book series.
Seagulls are sea birds occurring worldwide along coastlines. Unlike some other sea birds such as auks and albatrosses, sea gulls tend to stay near shore rather than venture out to the open ocean. Though there are over 50 species of seagulls in the Family Laridae, most are some variation of a white or grey base color with black markings.
Seagulls are generally very intelligent and have even documented using tools. They are highly successful and have adapted quite well to human presence.
In particular, the Lesser black-backed gull (Larus fuscus) has been mentioned in the Book series. This seagull migrates up and down the coastlines of the British Isles to West Africa, has a nesting ground in Iceland, and occasionally flies over to North America. Some Vikings would have been familiar with this species.
Though edible, seagulls are rarely eaten. It is possible historic Vikings occasionally ate them, as they feasted on a wide variety of seabirds. Gull eggs are also edible, as seen in How to Train Your Dragon. The Book series also used seagulls - specifically their feces - as an epithet.
|“||The gulls' eggs were hatching on the rocks and the parent gulls dive-bombed Hiccup and Fishlegs when they came to the Long Beach to practice.||”|
|— Book 1|
Fishlegs has a hard time getting Horrorcow to hunt or fish, since she favors vegetables over meat.
|“||You could have that Black-backed Gull for breakfast, he's barely half your size.||”|
|— Fishlegs to Horrorcow|
Viking women at the Thor'sday Thursday celebration are compared to seagulls.
|“||Impressively large Viking women huddled in groups cackling like seagulls and downing whole mugs of tea in one swallow.||”|
|— Book 1|
Later, the Green Death kills several seagulls with his roar alone:
|“||The Dragon opened its mouth and let out a sound so loud and so terrifying that four or five passing seagulls dropped down dead with fear on the spot.||”|
|— Book 1|
Thuggory utilizes seagulls in a threat to Snotlout:
|“||YOU shut up or I will tear you limb from limb and feed you to the gulls, you winkle-hearted, seaweed-brained, limpet-eating PIG.||”|
|— Thuggory to Snotlout|
The feathers of seagulls feature in Hiccup's plan against the Green Death and the Purple Death, by making feather bombs to make the slightly asthmatic dragons sneeze.
|“||Now I want everybody to go down to the Gull's Nesting Place and collect as many birds' feathers as you can for the feather bombs.||”|
It is unclear where on the island the "Gull's Nesting Place" is located.
|“||My master will tear this Hiccup limb from limb and throw him to the gulls.||”|
Dawn over the Archipelago in winter is likened to the color of a seagull.
|“||the sky was no longer black but the bluey-grey of a seagull's back, and the sun was coming up fast from behind the Mazy Multitudes.||”|
|— Book 4|
Gobber the Belch references seagull stool in an epithet when he says, "Nonsense and gull-droppings!"