Is this cat vomit?

Hey all

As I was leaving my house today, my father who was visiting noticed this right next to my front door:


He immediately assumed it was River's poo, but I didn't think it was - it looked nothing like River's poo, even at his loosest his stool doesn't clump together like this, and it had the wrong consistency. His litter tray is right down the hallway (and has been used). 

When I got back and investigated further, I noticed it had green patches in it - in fact it matched, albeit with paler colours, the palette, if you will, of his food:


I've never known him to vomit before so I'm not sure but - could he have? He's been acting completely normal, no behaviour changes, no diet changes (he did have some cat milk yesterday, but he's had them before with no ill effects - and he had his dewormer pills last Thursday, tho he did resist taking and swallowing them if that's relevant, tho I eventually got him to).

This is the first time I've seen this, so Idk if it is vomit, weird excrement - or even nothing to do with River at all (though the matching colours would seem to lean otherwise)? And it being the only time this has happened - if it doesn't happen again, should I just dismiss it as a one off?

Thanks

Oh, he did rip off and swallow the feathers from his toy I think yesterday or the day before if that's relevant? Just listing recent dietary stuff.

Yes.  Has he eaten anything leafy?  Something has definitely upset his tummy.

Are you asking if he's eating anything leafy because of the leaves in shot? - if so ignore them, like I said I found this near my front door, where leaves are blown or dragged in. Of course there's nothing to say he hasn't eaten any of said leaves but it would be impossible to tell. He's always had access to that part of the house though, it's not recent for what that's worth.

Most cats throw up now and then. It's not necessarily a bad sign unless it happens frequently. Since it looks like his food I'd say it probably is vomit.

Sometimes mine will spit back up (almost in that consistency) their meal if they ate too fast or are trying to cough out a hairball. I'd keep an eye on him to be sure he was otherwise behaving normally, but wouldn't worry if it wasn't something that was reoccurring.