To the partisans of Kyogre in the great eternal war which literally shapes Hoenn, Wingull is also known as the bird of victory.
Wingull spend their days flying above either the open ocean or those perpertual battlefields between land and sea called beaches. Whenever a wild Wingull is carried inland by wind currents or simply explores too far in that direction, it is almost always shot down and killed by Groudon worshipers, who fear their use in reconnaissance and espionage and despise them for being water pokemon. Team Aqua and its predecessors have historically used Wingull spies, after all, although they were far better trained in stealth than their wild counterparts.
Wingull is called the bird of victory because the only time when they can venture inland unharmed is after the sea triumphs over the land in battle. With no one left who is capable of knocking them out of the skies, their long, white, blue-striped wings take on the character of a flag of triumph, soaring triumphantly over the home of a vanquished foe who can offer no further resistance.
But although pokemon and trainers fighting for Kyogre and Groudon wage war again and again, the sea merely gains or loses territory; it never disappears or becomes strong enough to swallow Hoenn whole. Until the forces of Groudon regroup and rejuvenate, the victorious corsairs loot at will, and none do better than Wingull, the great pirates of the avian world. While whole cities, their armies beaten, move themselves inland to survive, these pokemon take their chance to loot everything from valuable jewels to poke balls in their long beaks. And then the Wingull carry their loot away, either to ransom it back for food or to line their opulent nests, and they wait for water's next conquest.