Goose or Swan Egg

[JessesGirl91016]

Found this egg just laying out in the open near the bank of a small lake. It looks very white in the picture but at times it has a bluish hue. I’ve narrowed the mystery down to these two options. Thoughts? Thanks in advance.

 

[nuthatched]

Go put it back, it's illegal for you to possess a migratory birds egg.
It would be hard to say what laid it.

 

[Zenmonkey]

Looks like a goose egg, but that's likely because I don't know what a swan egg looks like.

I think the usual swans you'll find in a park setting are not protected, but the geese are likely to be Canada geese and absolutely are protected.

Also ethically, those are smart birds. I'd expect there's a best nearby and a stressed mother.