You can hunt upland birds with any shotgun. Period.
However, personal preferences and opinions abound. A few things to consider:
- early season hunting when the leaves are in the trees often results in tighter spaces, shorter visibility, and closer shot presentations. At this time of the year, barrel lengths around 26" or 28" are certainly no disadvantage. Also, Improved Cylinder and Modified chokes can be practical.
- Later in the season once the leaves have fallen, 28" to 30" barrels aren't out of place. And, Full and Modified chokes suit the longer shot presentations.
- generally speaking repeaters are desirable, but they don't have to be the usual pumps and semis; break-action doubles are really your best choice. Why? Because the two barrels can each have their own trigger and different chokes. Double triggers and F/M or M/IC choke combinations allow a hunter to select the appropriate choke for the individual target distance. It might sound like you might fumble with the triggers, but you get good at it quickly.
A 14" barrel isn't too short, but I know without asking that it's on a pump or a semi. Right there, you're losing the dual choke/dual trigger advantage. The other advantage to longer barrels is the smoothing effect they have on your swing. In order to be or become a good wing shooter, you need guns that are neither too light, nor too heavy. Too light means the recoil is higher and the swing is whippy (or erratic). Too heavy helps absorb recoil, but requires much more strength and control to accelerate toward the fleeing bird.
In BC, the wild game tends to be blue grouse and spruce grouse. Both species are known to sit calmly watching you approach because they truly think they're invisible (which most of the time they are). So, if you hunt without a dog, you could see a fair number of perched and sitting birds. Any shotgun with a full choke should be able to decapitate a bird in a tree. I wouldn't expect as good results with the ones on the wing, though.
Since any day in the woods beats a day at work, I'm confident you'll enjoy yourself no matter what you choose to carry. One last thought - use the lightest loads you can find (7/8 to 1 Oz type stuff). Unless you're hunting Pheasant or Sharptail, you don't want too much lead in the air. It only takes a couple of pellets to drop a grouse.