Pluses for birds are that forest fires consume dead logs, clearing spaces for new, native vegetation. Fires get rid of competing (and often invasive) vegetation, and cause several tree species to release seeds of new trees. Forest fires (which are predominantly a natural occurrence) add lots of carbon to the soil. All this allows dense, new vegetation to grow, adding many, many new nesting sites and food sources.
Most birds migrate at night. At night, the winds are calmer, making flight easier. At night, most predators aren't active, and the temperature is cooler. Most songbirds, however, are normally active during daylight only. So for a short period just prior to and during migratory flight, songbirds' bodies are adjusted naturally - an activity called "nocturnal restlessness".
In north Texas, we may see it as our hummingbirds migrate south for the winter. That's why I advise leaving nectar feeders up through the first week of October. This helps feed stragglers from up north; and you may see your feeder a lot emptier each morning.