Fueled by Nectar

Hummingbirds migrate by instinct. Fewer hours of daylight trigger hormonal changes that cause the urge to fuel up and fly south. Your backyard hummers will leave while nectar-rich flowers are still in bloom and feeders are full.

• Fueled by nectar, hummingbirds double their weight as they prepare to fly hundreds or even thousands of miles. Watch your hummingbirds go on a feeding frenzy before leaving their breeding grounds.