Somethings up with the magnetic pole perhaps?
I had the same thought. Saw a NOVA show on PBS the other night about mag pole reversal. A scientist has built a pretty convincing model of reversal, and ancient lava flows show reversals every 200K years or so. Right now, we are 500K overdue and the anomalies in the magnetic field predicted by the model are rapidly appearing. According to one lava flow study, once the critical point is reached, reversals can happen in minutes. Birds, sensitive to mag field for navigation, may have become disoriented by an anomalie and simple flown into the ground.
That is what I was wondering, I know the poles switch direction now and then. Reminds me of the movie "Core".