What Happened to the Birds

I filled the bird feeder up with seeds about a week ago and hardly any birds have come to the feeder in that time. This is very unusual and most of the time the feeder is swarming with birds right after I top it off. We always see a flock of the riffraff sparrows hanging around for days until the level drops. It has been cold and snowy but I really was expecting the birds to be doing their regular feeding. The birds have also not been visiting our neighbors feeder either. I've only seen a chickadee coming around a little bit in the past couple of days.

We also haven't seen squirrels around. This has made up suspect that there is a predator hanging around nearby. We often have hawks coming around but they usually don't stay very long and the animals return in an hour or so. This has been days. A week. 

It has also been a little weird that I have seen bunny tracks in the snow several days in a row in fresh snow. Probably early in the morning or maybe later in the evening but I haven't seen any rabbits in the yard lately. It's all been very strange.