The next time out, Jake and I made it up the hill early and then a slight mist began to fall. It only fell for a half hour or so but with the temperature being somewhere around 25 degrees everything turned to ice. Jake didn't seem to be effected by the frozen rocks and ground and found plenty of birds.
A post script to this post. It's amazing how hard it is to find the flushing birds on these dark overcast days. Usually by the time I would finally get on a bird they were at the far end of my shooting range. Especially when dark brush was involved.