Migration usually happens twice a year, in spring and again in autumn.

The longer version

Migration moves birds between a breeding area with long summer days and plentiful insects and a wintering area with milder weather and available food. The return is not simply the reverse in time. Spring travel is faster and more direct, because arriving early wins the best territory, while autumn travel is more relaxed.

Timing is triggered mainly by day length, which does not swing from year to year the way temperature does, so birds leave on schedule rather than on weather. Fattening begins weeks earlier. Some populations migrate only partly, with birds in milder regions staying put, and the split can shift as winters change.

Where this entry sits

Here you will find feathered trivia about flight, migration, nests, eggs, and the songs birds sing. Expect short surprising facts on penguins, owls, hummingbirds, and other familiar birds from gardens, forests, wetlands, and distant coastlines. The full list sits on the Birds page, where every entry is listed in order.