Would this be rule wise legal? - When birds attack.

[Ragmon]

What's the Stealth check on a bird? They get a size bonus to Hide.

Its hide is +10 (2 dex, 8 tiny), dex only for move silently.

 

[Ragmon]

Just remember to keep in mind the difference between "can" and "should" - it's a neat trick, but going all Omen on the citizens is probably something to keep in your pocket for special occasions.
Now admittedly, I have a 4E pixie druid whose entire schick is that he spends most of his time as a talking crow, but he's also tricked out as a charger and hitting the accepted striker damage benchmarks while fighting in his crow form. Poking things for a single point of damage doesn't have much use in a serious fight, but outside of fights it's definitely a useful tool. And just like any other tool, you don't pull it out for every job - just the ones where it's the best choice. Unless your character's supposed to be a serial killer picking off random peasants or a professional kobold hunter, there won't be too many targets where Tweety-ing them to death won't be a ridiculously ineffective and time-consuming way to take them out.

Yea I don't plan on to abuse the ability, our DM is rather sensitive to maxing out the use of abilities, like prestidigitation and hat of disguise's disguise self.

Interestingly enough on the fly I found a great use for the bird, mini-mapping.
We were assaulting a walled hobgoblin fort and mid combat I broke my bow (crit fail) and the only useful ability that I had was the bird, for scouting the movement of the hobs.

 

[(Psi)SeveredHead]

Just remember to keep in mind the difference between "can" and "should" - it's a neat trick, but going all Omen on the citizens is probably something to keep in your pocket for special occasions.
Now admittedly, I have a 4E pixie druid whose entire schick is that he spends most of his time as a talking crow, but he's also tricked out as a charger and hitting the accepted striker damage benchmarks while fighting in his crow form.

Is the power you're using Dark Wings? I thought it didn't let you attack. (Neat if it does.)