Just how much of a success story is the sandhill crane recovery? Looking back more than 10 million years, the crane itself is one of nature's biggest success stories.

As close as these cranes came to flirting with extinction, they have a remarkable fossil history. The oldest, no-argument sandhill crane fossil is 2.5 million years old. That puts it more than a million years older than the earliest fossils of most living species of birds.

According to Wikipedia, a 10-million-year-old crane fossil from Nebraska is either a sandhill crane or its direct ancestor.

Since life showed up on planet earth, the crane has outlasted millions of species – 99 percent of all species that have ever inhabited this planet are now extinct, according to a March 2014 Smithsonian Magazine article on the sandhills’ annual migration to the Sandhills of Nebraska.

"Nature got it right with cranes," the Smithsonian Magazine wrote. “They have been around since the Eocene Epoch, which ended 34 million years ago. They are among the world's oldest living birds and one of the planet's most successful life forms. The particularly successful sandhill crane has not changed appreciably in 10 million years."

Since mid-February, in one of the grandest migrations on earth, upwards of 600,000 sandhill cranes, descend on an 80-mile-wide swath of the central Platte River in Nebraska. By April, some 80 percent of all the cranes on earth will show up in this one piece of Nebraska river bottom.

Birds who over-wintered in Texas, Mexico, Arizona and New Mexico fatten up in the Platte River corn fields before heading north, some flying as far as away as the Arctic. And Montana.

Around September or October, some 20,000 sandhill cranes eventually migrate over Montana, going south for the winter.

Just how rare was the sandhill crane at the turn of the century? Quite rare, according to Hansen, "but no one was keeping data back them."

So no one knows how many of that last 1940 group of cranes were in Montana? Nope. James Hansen of Montana Fish, Wildlife and Parks does have a rare copy of the 1921 "Birds of Montana" by the Cooper Ornithological Club of Berkeley, Calif. It lists sightings of breeding pairs in "Midvale, now Glacier Park, 1914; Flathead Lake, 1903; Bitterroot Valley, three sightings in 1910;" and Migrating cranes sighted in Custer and Dawson counties, Sept. 22 1893; Fergus County now rare, 1903; Fort Shaw, Feb. 28, 1868; Big Sandy April 6, 1905; Terry, Nov. 10, 1903; Stuart, Silver Bow County, April 16, 1911; Chouteau, April 28, 1912; Bitterroot Valley, April 20, 1912; and Billings, April 12 and Sept. 15, 1918."

And that's all, for Montana. (The book also lists a 1912 sighting of a whooping crane in Billings.)

The crane is a beloved totem in Asia, known as "The Lord of the Feathered Tribe" in China and "Honorable Lord Crane" in Japan. In Celtic mythology it is sacred to the King of the Underworld.

It's now April, which to Hansen always means the sandhill crane is already here.

More so than the arrival of a robin, which can stick around through a mild Montana winter, the crane heralds the onset of spring. Hansen, a Billings resident, usually sees his first crane March 5.

"That's when I know it's almost spring,” he said.