This is Bird Note.

Sand Hill cranes are famous for gathering in the tens of thousands during spring migration in Nebraska.

They roost overnight in shallow prairie rivers. Then, in the early morning, they take off.

Within these massive gatherings of cranes are many smaller groups, tight-knit family units.

A pair of adults might travel north with their young from the previous summer, along with

grown-up offspring from several years ago.

Okay. along with grown-up offspring from several years ago. In the summer, cranes find places to nest in wetlands and open areas throughout the northern U.S. and Canada.

They'll raise up to three chicks over the season.

Sand Hill Crane families form a close bond. They typically will stick together for the journey south and the winter, even in large flocks.

The parents will often stay together for the rest of their lives.

Cranes may even recognize family members from many years ago.

Researchers once observed that two 20-year-old brothers and their mates formed a family

group for the fall and winter.

After decades, the family tie still held strong.

For BirdNote, I'm Ariana Rimmel.

BirdNote is supported by the Cornell Lab of Ornithology.

Learn more about the lab and their online bird academy at allaboutbirds.org.