Lots of bees owned by commercials and I would guess that most, if not all, of the bees for almonds come from commercial beekeepers. Almond pollen is actually pretty good nutritionally but the bees are exposed to chemicals that have negative impacts--fungicides used on almonds are especially hard on bees. The Central Valley is basically a floral desert until the almonds bloom so bees generally have to be ramped up to get the job done; prior to almonds, bees are running on stores or nutrition provided by the beekeeper. And, as others have said, poor habitat conditions, neonics, etc all take their toll. Beekeeping isn't what it once was in many locations throughout the US and beyond. The sad thing is that it will take a MAJOR crisis to change things. Sadly, 44% loss won't do it! In my view, if you keep bees in stationary locations you shouldn't have to feed them protein or syrup to keep them alive if the habitat is worth a hoot--the bees tell us a lot about the quality and sustainability of specific locations. There are some locations where habitat is of adequate quality but many are not. If you're in a good place, be thankful--the world is a changing. The remarkable thing about bees is that they respond so positively when fed quality food-either from the landscape or from artificial foods provided by beekeepers--we can make up numbers fast. When there is no longer an economic incentive for commercial beekeepers, I would guess that hive numbers will drop precipitously. Around here, most of the commercial guys I know did well this past winter but there were some very large commercial outfits that reported HUGE losses.
