August: Migration Underway
August brings the first push south, and adult males are the first to leave. The juvenile Rubythroats and mothers that remain look so much alike that most of us can't tell the difference. The babies have no memory of past migrations. They do not migrate with a parent. They just follow their urge to put on a lot of weight, fly in a southerly direction for a certain amount of time, and find a good place to spend winter. Hummingbirds migrate at the time when their food is most plentiful, and they leave when they are fat enough. Some follow the coastline of the Gulf of Mexico. Many—but not all—fly 500 miles nonstop across the water to Mexico and other Central American countries. It's a mystery how individual birds make the decision.

Image: Harlen E. Aschen