If seagulls fly over the sea, then what flies over the bay?

Bagels.

Captain Planet Gull: "Give me those chips and I'll poop on you!"

You: "... don't you mean 'or' you will poop on me, not 'and'?"

Captain Planet Gull: ...

You: ...

I never knew that. I thought it went from beagle to seagull and then on to eagle…

Don't forget heartgulls. Everyone always forgets heart.

Wrong.

Seagulls imply the existence of Rivergulls, Lakegulls, Mountiangulls, Desertgulls, Forestgulls, Plaingulls, Valleygulls, Hillgulls, etc.

I've seen many seagulls in my life.

But I've never seen any of the others.

And that's terrifying. Stay vigilant.

I think a "landgull" would just be a pigeon

In light of the above, then, I hereby propose that squirrels get renamed to "treegulls."

It's all fun and games until the firegull nation attacks.

If there are armadillos, where are the legadillos?

Bay-gull. Bagel.

also, spacegulls

Reminds me of a John Hodgman bit - we have ice hockey, field hockey, and air hockey, implying the existence of fire hockey.

Most of what we consider "seagulls" dont actually go out to sea. It's all lies.

I used to study animal management and there was a lecturer who wrote his uni thesis on "seagulls" and any time he heard someone call them seagulls he'd shout down the hallway "They're herring gulls!"

Don't forget THA GOOD SHIP MERRY GULL!

Long ago, the four gulls lived together in harmony. Then everything changed when the fire gulls attacked...

Don't forget bay-gulls. They love fish, especially smoked salmon

We have Baygulls. They are tasty with cream cheese.

Heartgulls

I live in Colorado and there are gulls here, we are far from the sea.

Water-Gull. Earth-Gull. Fire-Gull. Air-Gull. Long ago, the four nations lived together in harmony. Then, everything changed when the Fire-Gull Nation attacked.

Water. Earth. Fire. Air. My grandmother used to tell me stories about the old days, a time of peace when the Avatar kept balance between the Seagulls, Landgulls, Firegulls, and Airgulls. But that all changed when the Firegulls attacked.

You have to go pretty far back (to proto-Celtic, it looks like) to find a linguistic ancestor for the word "gull" that doesn't just mean "that specific bird."

But in proto-Celtic, it looks like "weilanna" probably meant "wailer." As in, "one who wails," though we don't know exactly what the suffix "-anna" means. A similar word in that language would've been "wailos," which even though it sounds similar seems to have been unrelated to our modern term "wolf," as it comes from a different proto-indo-european root.

Anyway, the word "gull" does refer to the sounds that it makes more than anything else. So in figuring out what a landgull, airgull, and firegull might be, we need to find something noisy. Or just something annoying, given the derisive connotation of "wail."

Edit: This is, of course, assuming that we're looking for different existing types of animals to be these creatures, rather than just (for instance) creating new, elemental forms of gulls; or "reskinning" seagulls with different elements; or inventing all-new animals to fill those roles.