I hunted Northern Quebec this passed year from Dec. 4-8th. There were more antlered caribou than you could shake several thousands sticks at. A lot of bulls have lost their horns, but there are more than enough to go around. Our largest bull had a 47" spread and 2 of our hunters had a bull standing 50 yds. away with a 5ft spread. (They had just filled their last tag).
There are two major herds that summer in Far northern Quebec, One has 880,000 animals and the other 240,000 and they all want to cross the GranTiegis Highway to get to the other side. In the 1999-2000 season, sport hunter took a total of 16,452 caribou in the combined fall and winter hunts. That is a lot Caribou left running around. Another thing, most of the animals have little or no contact with man, so it's not hard to kill them when they're crossing the ONLY road for 400 km. The trick is to find them when they're NOT at the road.
Winter caribou are not any dumber than fall caribou, they just taste better.
Your hunt will be what you make it, you want to shoot them on the shoulder of the road, or do you want to catch them running over the ridge in a spruce woods.
And remember THERE WILL ALWAYS BE A BIGGER CARIBOU COMING. Do not shootout too early and if you have time wait a day before you shoot your second animal. It can be quite a rush have 500 to 700 caribou run by you and still be objective about your choice.