The diminutive hummingbird is one of the most iconic avian species found in the Sonoran desert, and experts say there is much more to them than beauty, grace and speed.

Sheri Williamson, a naturalist and co-founder of Southeastern Arizona Bird Observatory, says the group's longest-running project is monitoring of hummingbird populations along the San Pedro River.

The research began in the 1990s and continues, providing experts and volunteers an opportunity to get close to hummingbirds and learn much more about their habits and behavior.

It includes an amazing ability to travel for thousands of miles in some cases, or to be very protective of their territories. This explains their occasional efforts to keep humans and other relatively large animals at bay.

"They're ferocious little creatures," Williamson says. "My husband likes to say that if hummingbirds were the size of ravens, no one would be safe."

Williamson says Arizona has more than a dozen recorded species of hummingbirds, which along with Texas is the most hummingbirds of any state.