Tiger vs Herring Gull

Lately, I've been working on a poster for the upcoming roller derby's match opposing Oslo to Brest (France).
The tiger embodies Oslo, whose nickname is "Tigerstaden" (The City of the Tiger). So, to face the norwegian felidae, I choose a herring gull : Brest being a port, I failed to see any other animal living close to the city to personified it.