An Educator's Guide . San Francisco Bay National Wildlife Refuge. Most birds do not fly nonstop between these areas although they arc capable of it. Timing of the migration is correlated with seasonal temperature changes. This ensures that when the birds reach their nesting areas, the ground will not be frozen.
Wetlands are important as they provide an area where the birds can feed and rest along the way.
Without these local wetland areas, many birds would not get enough food energy to sustain them throughout their migrations. The Pacific Flyway is the migration route chosen for this activity. In the United States. If a bird flies between Argentina and Alaska, it will cover between 7- 8,000 air miles. Birds fly faster the closer they get to their northern nesting grounds because there is less time to nest and raise young before freezing weather comes again.