Focus on Arts and Ecology

Wildlife biologists counted the birds—likely lured by the region’s mild winter temperatures—during their first aerial survey of the season. 

By Sarah Kuta, February 22, 2024

A record number of sandhill cranes arrived in central Nebraska during the first week of their annual spring migration, likely lured by mild winter temperatures.

Each spring, hundreds of thousands of the tall, long-legged birds begin making their journey north to breeding grounds in Alaska, Canada and eastern Siberia. Out of all the world’s sandhill cranes, 80 percent use Nebraska’s Platte River as a pit stop, where they fatten up on corn kernels left over from the previous fall’s harvest.

Their yearly Nebraska stopover usually lasts from mid-February to mid-April, with individual birds staggering their arrivals and departures. Each bird spends about a month in the state, with their numbers typically peaking around mid-March at roughly 500,000 cranes.

Once migration begins, wildlife biologists at the Crane Trust in Wood River, Nebraska, conduct weekly aerial surveys to count the birds. This year, during their first count of the season on February 14, they recorded an estimated 38,000 sandhill cranes—the highest first count on record since they began conducting the surveys in 1998. Most of the birds were found along an 80-mile stretch of the river between the towns of Chapman and Overton.

During a typical year, between 6,000 and 8,000 sandhill cranes have usually arrived by the first count. Last year at this time, biologists counted 6,400 cranes.

Scientists weren’t surprised by the numbers, however, as they match up with patterns they’ve seen during previous mild winters.

“The winter of 2021-2022 was also a fairly mild winter, and we had around 27,000 cranes on Valentine’s Day that year,” wrote Bethany Ostrom, a wildlife biologist who conducts the aerial counts, in a February 15 update posted on the Crane Trust website.

Central Nebraska also saw a high number of sandhill cranes during the recent fall migration, with some birds even opting to spend much of the winter in the region. An estimated 14,000 to 15,000 sandhill cranes—and two rare, endangered whooping cranes—stuck around for the holidays.

“We do have occasional small groups of cranes overwinter… but we have never before seen this large of a group stay here for so long,” wrote Ostrom in a preseason post on February 6.

Birders hoping to witness the annual congregation still have plenty of time to get to Nebraska to see the cranes. Though early counts can sometimes indicate when the birds’ numbers will peak, their arrivals depend more on daily and weekly weather patterns. Cold fronts, for example, can delay the peak.

“There are many factors that play into cranes’ decisions when to migrate, many of which we probably do not understand,” wrote Ostrom.

Sandhill cranes are one of the oldest bird species on the planet, according to the Iain Nicolson Audubon Center at Rowe Sanctuary in Gibbon, Nebraska. Archaeologists at Ashfall Fossil Beds in northeast Nebraska unearthed the fossilized remains of a crowned crane—a close relative of the sandhill crane—that’s estimated to be roughly ten million years old. The oldest sandhill crane fossil, found in the Macasphalt Shell Pit in Florida, is roughly 2.5 million years old.

The birds haven’t been visiting Nebraska’s Central Platte River Valley for quite that long—millions of years ago, the river didn’t exist. But, as soon as it formed near the end of the last ice age, around 10,000 to 12,000 years ago, sandhill cranes began stopping by, according to the center.

Birders from around the world often follow the cranes to Nebraska, waiting patiently at dawn and dusk in viewing blinds located along the river. The birds roost on the braided river’s sandbars at night, then take to the skies at sunup and head toward neighboring corn fields. They return to the safety of the river at sunset.

Sandhill cranes have a distinctive aesthetic: Standing three to four feet tall atop stick-thin legs, they have light gray feathers covering most of their bodies. Their crown is a deep crimson color, and they have white patches below their eyes.

In Nebraska, the birds spend most of their time eating—they can put on as much as 20 percent of their body weight during their sojourn in the Cornhusker State. But they also use this time to strengthen their social bonds with one another, especially their mates. Sandhill cranes can be seen “dancing” with each other in the fields, a behavior that involves jumping up and down, bobbing their heads and extending their wings. As Katie O’Reilly wrote for Sierra last fall, the annual gathering is “part family reunion, part singles dance, part inter­-flock house party.”

Even when they’re not visible, cranes announce their presence with a unique trilling sound called bugling. When tens of thousands of them bugle at the same time, “the sound is deafening,” writes Amber Travsky for the Laramie Boomerang.

(Sources: Smithsonian Magazine)