I based my assumption that his birthday is 30.11. for this 水野英多 on Twitter: "歩おたおめ http://t.co/Ln4LDwdotH"

But because of timezones, it might actually be 1.12.

I have no idea how twitter works, so can anyone confirm, when exactly it was posted?

I'm a bit bad with twitter times as well but according to Spiral's Japanese wikipedia site, Ayumu's birtday is 1.12.

Ah, ok. Thank you <3 I couldn't find the date anywhere in English. With the mangaka's twitter and that wiki, it should be official enough.