DECATUR, Ala. (AP) — In flooded agricultural fields near the Tennessee River, tens of thousands of sandhill cranes stand tall among broken corn stalks and shallow water searching for corn, berries, seeds and insects.

The sound and sight of so many cranes clustered together creates a chorus of trills, trumpets and honks throughout the Wheeler National Wildlife Refuge Center in northern Alabama during the winter.

The annual migration of sandhill cranes brings bird-watchers in droves to see the tall birds up close, but also the chance to catch a glimpse of the rare and endangered whooping cranes that migrate in much smaller numbers to Wheeler. Alongside the cranes, plenty of other birds can be spotted at Wheeler, including geese, ducks, bald eagles, kestrels and hawks.

“It’s a birder’s paradise,” park ranger David Young noted.

The cranes, with their distinctive red foreheads and gray feathers, fly to Alabama from the Great Lakes annually. The sandhill cranes started staying overwinter at Wheeler starting in the mid-1990s and the numbers increased dramatically in the mid-2000s, Young said. Last year, the sandhill population that wintered at Wheeler reached a new record of 30,000 cranes.

“Here in the Tennessee Valley, we have three things that these cranes need,” Young said. “The wide open fields here around our visitor center. The leftover crop and the natural foods that they like to forage on in those fields. And then open mudflats and shallow water on the Tennessee River and its tributaries.”

The refuge has become a hotspot for birders to break out the binoculars and even get closer to the 4-foot (1.2-meter) tall cranes as visitors stay hidden behind photography blinds and a two-level observation center. An annual Festival of the Cranes in January brings more attention and visitors.

The cranes put on an impressive show, dancing on their slender legs, flapping their wings and sticking their long beaks in the air to vocalize with purring and squawks as they socialize.

Diana Maybury-Sharp, from Birmingham, regularly comes to Wheeler with friends to hike and look at birds.

“It’s pretty extraordinary. I’ve seen them in other parts of the country where there were just a few,” Maybury-Sharp said. “They’re not vocal like they are here. There’s so many here that it’s an unusual experience.”

The whooping cranes, part of the eastern migratory population that comes from Wisconsin, started migrating to Alabama in 2004 and their population is about between 12 and 20 each winter, said Young.

Whooping cranes were nearly wiped out in the early 1900s by hunters and loss of habitat from farming. Recovery and reintroduction efforts have slowly increased their wild and captive populations to more than 800, according to the International Crane Foundation.

Migratory whooping cranes depend on freshwater wetland habitats in Texas and the southeast, which could be affected by rising sea levels and droughts, according to the foundation.

They are sometimes hard to spot amongst the shorter crowd of sandhills, but their height and white feathers help them stand out. Young said the migration patterns of the cranes may change depending on the climate trends of both their nesting locations and their winter homes.

“It’s hard to say how long they will continue to winter here in north Alabama,” Young said. “And maybe they may not need to come this far south in the future. But for now, we’re really enjoying their presence and making sure to provide that habitat for them and the opportunity for people to view them here too.”

Rob Broeren, of Huntsville, brought along his telephoto lens and camera and found a good spot to practice his wildlife photography hobby. He comes to the refuge about a dozen times each year to photograph the birds and ducks.

“You just need to be patient and wait for them to do something interesting and make their calls,” Broeren said. “You get that cool shot and that’s a good day.”

Broeren was scouting locations for friends coming in from out of town who wanted a chance to see the rarest of cranes.

“Birders are big on a checklist of seeing lots of different birds,” Broeren said. “And so people that haven’t seen that species because it is quite rare are willing to drive kind of a long way if they think they have a good shot of seeing it.”

The sandhill cranes will start leaving the refuge in mid-February. Young said he notices a lot more agitation and activity when the birds are signaling they are ready to make the journey back to their nesting grounds.

“It’s usually on a day when we have some sort of a south wind,” Young said. “They’re smart and they will ride the wind back to their breeding grounds whenever it’s most convenient for them.”