I wonder if the reason this Hawk is hunting is because it knows something is coming.  Wildlife have an interesting sixth sense.  They are somewhat aware (as aware as an animal can be) of major impending storm systems, things like cold fronts and tropical storms. I suppose it is more like a reflex.  Evolution has prepared them to survive these sometimes catastrophic events.  They have been evolutionarily tuned to prepare for potentially harsh conditions.  This one is probably gorging on as many small creatures as it can so it will have an easier time during the upcoming rainy and windy conditions. Nature seems to have a balance, and the creatures are in harmony with it.

Read more about the Red Shouldered Hawk:  Red Shouldered Hawk Information