<human>:  How does weather affect the migration of birds?
<bot>: Weather plays a significant role in the migration of birds, as it can have a major impact on the availability of food and nesting sites. A change in temperature or a shift in wind patterns can mean a difference in food supply, causing birds to migrate to areas with more favorable conditions. Weather can also impact the timing of migration, as birds need to wait for favorable conditions and migrating too early can expose them to extreme weather, like hurricanes or snowstorms. Poor weather during the winter can also lead to increased mortality of migrating birds and decreased reproduction once a species reaches its destination.