Hummingbirds are back; they're hungry and they still have a long way to go on their trip to their winter homes.

The annual migration started this year about two weeks later than usual, Mark Klym, hummingbird specialist for Texas Parks and Wildlife Department, said. The Rio Grande Valley is in its second week of the birds' seasonal visit, with another four to five weeks to go.

The adult males are usually the first to arrive, he said, with the females and juvenile birds arriving now.

What hasn't changed from last year is the need for backyard birders to set out feeders to fortify the tiny winged travelers that will migrate by the thousands over thousands of miles through the Valley to Central America.

Feeders are particularly important, experts say, as dry conditions have persisted for a second year in Texas, reducing the native flowers on which the birds feed during their travels.

The National Weather Service's drought monitor map shows that most of Texas remains abnormally dry, with areas of extreme and exceptional drought. Absent a tropical storm, any rain that falls now is unlikely to change this condition.

Norma Friedrich of the Arroyo Colorado Audubon Society said she has observed the toll that the ongoing dry conditions have taken on even native plants. The plants at Ramsey Park look "pitiful," she said. While the native plants will revive once the rainfall increases, the migrating birds need help now.

Hummingbirds are voracious eaters because they burn so much energy, according to the TPWD website. They fly at speeds of 30-60 mph and must feed every 15 minutes.

They are the only birds that can hover, fly up, down and backward. Hummingbirds do not soar as other birds do and must keep their wings in constant motion to keep them in the air, the TPWD website states. The birds' chest muscles weigh one-third of their body total weight, and hummingbirds' hearts are proportionately the largest among birds.

"Translated into food intake, to keep up with the energy a hummingbird burns each day, a human would have to eat 285 pounds of hamburger or 370 pounds of potatoes," the website states.

Their main food source is sugar from nectar in tubular-shaped flowers. Without the flowers, hummingbird feeders containing a sugar-water mixture can augment the natural food.

Hummingbirds find feeders the same way they find flowers: by sight, Klym said. They are attracted to bright colors, especially but not limited to red.

"They treat feeders like flowers," Klym said, and called blooming plants around feeders a "garden buffet."

Once the hummingbirds find a food source, they are likely to return to the same location every year for their five- to seven-year lifespan.

Klym said the hummingbirds can become acclimated to feeding from feeders, but they readily return to foraging when they move on to Mexico and Central America, where they're less likely to have human assistance for food.

When the birds have found a feeder, they sometimes become aggressive toward each other, Klym said. The birds' tail feathers will fan and they will chase away other hummingbirds, to claim this food source.

"Eventually the instinct to feed will overtake the instinct to be aggressive and protective," he said.

Friedrich said the hummingbirds most commonly seen in the Valley are the ruby-throated, black-chinned and Rufous varieties. Klym added calliope, Allen's and Anna's hummingbirds varieties. Buff-bellied hummingbirds are year-round Valley residents.

Friedrich said the hummingbirds are visiting feeders in her Harlingen backyard, but they are also attracted to the native plants that are growing nearby.

She recommended planting bottlebrush, esperanza, native turk's cap, yellow sophora and pride of Barbados to attract the migrating hummingbirds.