Every March, more than half a million sandhill cranes - the entire mid-continent population - converge on the Platte River in central Nebraska. Each bird spends about three weeks feeding and building fat reserves for the rest of their northern migration and the grueling nesting season.

In the evenings, the cranes come to the river itself to roost overnight. They favor broad channels with abundant bare sandbars where large groups of cranes can congregate in large noisy masses of up to 50,000 or more. As the sun starts to go down, wave upon wave of sandhill cranes drop gracefully into the river like so many floating dandelion seeds.

Not surprisingly, this wildlife spectacle draws bird watchers and nature enthusiasts from around the world. Crane watchers can drive rural roads to watch the cranes in the fields and meadows during the day, and stand on riverbank platforms (or reserve space in viewing blinds) to see them come to the river at night. Besides cranes, visitors to the Platte in the spring can also see millions of ducks, geese, and other waterbirds.

The cranes spend the night standing on bare sandbars or in shallow water. Their noisy calls eventually subside enough that they get some sleep, but it's rare that the entire group is quiet for long - and any disturbance (real or imagined) can quickly set the birds to calling and shuffling nervously about again.

In the morning, the cranes leave the river and head to nearby meadows and cornfields to feed. On some mornings, the birds seem reluctant to leave their roost, choosing instead to loaf, feed, and even bathe in the shallow water. Other mornings, a foraging eagle or roving coyote can push an entire roost site into flight simultaneously, and the sound of many thousands of wings creates a deafening noise.

Besides the important task of feeding, cranes spend much of their day - in meadows and along the river - socializing.

Courtship behavior is common during the day, and can include elaborate dances with much leaping and ducking of heads, as well as stick tossing.

As March comes to a close, cranes start heading north to breed - mostly in Canada, but also as far north as Siberia. They usually leave on sunny days with a nice south wind to carry them. Cranes can average 35 miles per hour and travel 200-300 miles per day (up to 500 with a good tailwind). In the fall, they pass through the Platte in small scattered groups (we usually just hear them flying overhead) - providing us with just a quick glimpse of them, but a reminder of what we'll see at the end of the coming long winter.