Is my co-worker flirting?

I'm horribly bad in the department of flirting unless you are rubbing my leg or something.

However, at work I've felt for awhile now that a guy is subtly flirting with me but it could be my imagination.

So I've made a mental list

- If I look up or see him he will catch my eyes and gaze until either he passes or until I look down.

- Sometimes he blushes around me (not all the time) - like if I suddenly come into his view.

- Have caught him check me out a few times and when I look he quickly looks down to the floor, I don't look back again to see if he looks back at me

- Repeats what I say sometimes. Like if I say something he'll repeat it and giggle.

- On more than one occasion he has 'teased' me (lightly) via email or in a meeting. Like if I ask a question to somebody in the group he'll immediately say some smart/joking remark.

- Has attended my meetings when he had no reason to attend and just sat on the phone listening in without saying a word.

- Heard him asking about me, like what was going on with a project I was working, etc.

- Has gotten in my personal space when there was plenty of room.

- Has 'stuck around' when I'm conversing with other guys.

- Gives me sheepish smiles (the ones that don't display the teeth).

- Looks at me from up under his brow and stares deeply (no smile)

- Sometimes say hi how are you or have a lovely weekend or whatever (small talk)

These might not seem like a big deal at all and might not be, like I said I have a hard time deciphering. I am attracted to him now, in fact I feel a slight tension between us.
Is my co-worker flirting?
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