This is the weather all of a sudden changing. It has just randomly turned to freezing cold weather.
They assume that the birds are flying weirdly because of the sudden weather change. Later they attack them so they thinks something wrong so then later that evening the radio had said there is an emergency declared and to stay in there homes.
They had to go to the store and get supplies but they had attacked once again.
Nat and his family had to board up there windows. The birds had kept attacking so they had to keep safe. Nat also had to go get his child off the bus.
They had all stayed inside and safe all night hoping the birds would not come inside and attack them.
The next day there were many people hurt by the birds.