Udyr is one of my favorite champions to play and is literally a beast of the field of The Crystal Scar. This build includes damage and sustainability, both of which are important when you need to run and save one of your points from being captured. I take and early 2 points in bear form and one point in tiger form to prepare for the battle over the windmill.

My runes are chosen for damage output and early game survival that then scales into late game. The early game damage boost that the quints give you could possibly help win that first battle over the windmill. Not many builds include penetration so I take masteries that increase both my armor and magic penetration, and since Udyr does more autoattacking than letting his skills do damage I gave him more armor penetration in his marks. The seals are for flat armor, which is easy to come by in game if need be. The glyphs are great for scaling as the game goes. Dominion scales quite fast so having that extra magic resist before you get around to including it into your build is a good fallback.

My masteries are quite self explanatory. Flat damage and armor pen for auto attacks, the magic pen mastery for his tiger and pheonix for which optimize their output. Then 6 points to increase his defenses even more, making Udyr a hard hero to kill. And since Dominion scales so well and you never really build mana into his build, taking the mana mastery gives you a nice mana pool that won't have you going back to spawn to refill after every fight.

On dominion, start with boots of swiftness. This helps you get up to the Windmill faster and set up the team fight in the area that you chose, or in rare cases, even capture the point. I then rush an Ionic Spark to be able to push creeps off of capture points and deal more damage in fights. Sanguine Blade increases his survival by quite a bit, and this is where I find myself snowballing hard with him. I usually get Entropy in just one go, coupled with Udyr's attack speed it's a very good item for him and you will find yourself tearing you opponents to shreds. To finish off you build some resistances, the Force of Nature will allow you to travel between points, while the Sunfire cape adds to your damage and protects you.