Bird-watchers, take note. 

Danita Delimont/Getty Images

Have hummingbirds visited your feeders this season? Our appreciation for our tiny avian neighbors is well documented, which is why our eyes are always peeled for a glimpse of a hummingbird flitting from flower to flower in the garden. We’re constantly curious about what keeps these little birds flying, which is why we’ve gathered a few facts about hummingbirds to sate your ornithological curiosity.

Hummingbirds migrate.

According to the U.C. Davis School of Veterinary Medicine, “When hummingbirds migrate to the United States in the springtime, they cover 500 miles across the Gulf of Mexico, flying for 20 hours without stopping.” This is a major feat for these little birds. Before beginning the migration—which, in addition to everyday flight, can add up to thousands of miles a year—hummingbirds must store up energy. As described by the New York Times, hummingbirds “live on nectar and can pack on 40 percent of their body weight in fat for migration.” This prepares hummingbirds to endure the long Gulf flight and the physical strain it entails.

Hummingbirds are thirsty.

How do they nourish themselves? Hummingbirds drink nectar from flowers. They do this using their delicate, forked tongues, the edges of which are covered with extensions that trap drops of nectar for consumption. Their metabolisms are so fast and they have to eat so often that hummingbirds have evolved to conserve energy through torpor. The Smithsonian’s National Zoo & Conservation Biology Institute describes this phenomenon as “a very deep, sleep-like state in which metabolic functions are slowed to a minimum and a very low body temperature is maintained. […] Torpor allows them to check-out physiologically when they cannot maintain their normal 105 degrees Fahrenheit body temperature.”

Hummingbirds can fly backwards.

Hummingbirds are the only species of bird that is able to fly backwards. They do so regularly, and, as reported by BBC Nature News, research has found that hummingbirds’ “backward flight is efficient.” In fact, the research—which was conducted by University of California scientist Dr. Nir Sapir and others—shows that “flying backwards uses a similar amount of energy to flying forwards, both of which were more efficient than hovering.” Hovering is the birds’ third mode of movement. Hummingbirds are incredibly agile in the air. They fly forwards and backwards to move from plant to plant and perch to perch, and they employ the hovering mode when extracting nectar from flowers or feeders. While hummingbirds are adept at flying, their tiny legs and feet are less useful and are mainly used for perching.

WATCH: 6 Things Only Hummingbird Lovers Know

What are your favorite facts about hummingbirds? What will you be doing to attract these birds to your yard this year?