On the intro, a seagull can be seen flying towards Adventure Bay .
The seagull in the tundra, as shown in the episode Pups Save a Stowaway has black wings instead of grey. This is possibly a mistake or more likely it is a different species of seagull.
In Pups Save Walinda, a seagull ends up causing one of Marshall's elevator wipeouts (which is a running gag in the series) after it is attracted by some jelly that was on Marshall's tail. This marks the first time in the series that one of the Seagulls has been inside The Lookout.