mini marvels

HUMMINGBIRDS HAVE TRAITS THAT MAKE THEM ENTERTAINING, BUT THOSE SAME QUALITIES HELP THEM THRIVE.

- HEATHER ISHERWOOD

SMALL BUT SPEEDY.

TINY BUT AGGRESSIVE.

LITTLE BODIES, BIG APPETITES.

Hummingbirds are a study in extremes. They are the lightest North American birds. Most weigh less than two pennies at 3 to 4 grams. They have the fastest wings and heartbeats, the most efficient metabolisms, and the most minuscule eggs. The list could go on.

But hummingbirds are tough survivalists. Many of the actions that help them persevere also make them fun to watch. Here are amazing hummingbird traits and behaviors you might witness and the biological reasons behind them.

WHIRRING FEATHERS

Soon after Chris Clark, an associate professor at the University of California, Riverside, began studying Anna's hummingbirds, he wondered about their tails. "They're these little fighter jets," he says. "What are they doing evolving these really long tails that might slow them down?"

He discovered in his research that the stiff tail feathers of male Anna's make songlike sounds. These noises are part of the courtship display as the males dive to attract females' favor.

The wings of hummingbirds make different sounds-what Chris calls wing trills. "On broad-tailed hummingbirds, the males have this little notch in the outer part of their wings," he says. "They sound like a cricket when they fly."

Other species, including Allen's, rufous, and to a lesser extent ruby-throated and black-chinned, also have these trills. And in these birds, the trills are in place of songs, Chris says, with males using the sounds to declare and defend territory.