I agree with Otu, 2 Rooter is unnecessary. One Rooters piece is perfect because;

1. 4 M/S is almost perfect for a bear, you'd still run out of mana if you spam all your skills nonstop, but that almost never happens.

2. The Hit % it adds should be enough to have very good Hit % if you have dual spec stats.

3. The added Crit % is really a big bonus.

After 1 Rooter, my guess is you'd probably have about 95%+ Hit, you should focus more on Crit % if you want damage, which perfectly calls for Bellow's, Crit % Dodge % and Damage.

Your original set, your tank set, is actually really good if you look to tank. 35 base dodge and 173 armour is awesome for tanking, not to mention you haven't even maxed out Taunt (biggest dodge buff).

I'd keep that set to purely tank, you can kill too, but not as often. I personally like the Royal Helm, Rooter's Sword, Royal Plate, Cleaner's Shield as an FFA set. Good balance between dodge, armour, Hit and Crit %. Dueling sets can be different, very different.

For your skills, I'd choose 2 slashes only, personal preference is SMS and VS. Two shortest cooldowns and two highest damage per skill point. I would also max Taunt, it actually buffs dodge more than Evade does, and it's 0 mana cost.

Dex birds aren't the only problem, any ranged class is. Assuming you're melee While it's difficult to tell what exactly to do versus a bird/mage, there are ideal things that you should do, which Otu has mentioned.

Personal combo for a bird:

Beckon - CB - SMS - Stomp - (at this point it depends. If you get lucky crits within those 4 skills, the bird could be dead or could be low on health. If the bird is still alive, even before you Stomp, I would move towards the direction that Stomp would bring the bird. That way, right after you Stomp, cast HS. If you get it right, HS should stop the pushback of Stomp from pushing too far, allowing you to stay on top of the bird even after the combo.)

For a mage:

Beckon - HS - CB - Stomp. An int mage with shield on is rarely taken down in one combo. I use HS and CB before combo to fully debuff them as soon as they can cast spells again. You can stay out of range until your combo is ready again, then you can go Beckon - CB - SMS - Stomp. By that time, the mage's shield should be down which allows you to possibly one combo them.

I always remember, if I plan to go for a quick kill, CB is your bestfriend. -30% dodge at level 6 works really well in making sure that they don't get to dodge any of your skills. SMS has good damage and has a -10 armour debuff.

These combos are just my ideal combos, they don't always work because you have to factor in the statistics for all or some of your spells connecting, if they crit or not, and the PvP skill of your target. IMO, a bear is the hardest to PvP with, especially if you're melee. Not that it requires more skill, the class itself just requires too much "beating the odds" of Hit %, Crit %, and Dodge % to kill or live.