Experts monitored 58 breeding pairs of the endangered species in Wisconsin
Almost two thirds got together before at least one of them was sexually mature
Scientists believe there are benefits to the birds of long-term monogamy
This includes coordinating food foraging and protection from predators
PUBLISHED: 17:06, 23 November 2017 | UPDATED: 17:10, 23 November 2017
Rare whooping cranes often have childhood sweethearts.
Almost two thirds of breeding pairs get together before at least one of them is sexually mature, a new study shows.
Experts believe the finding demonstrates that there must be benefits to the birds of favouring long-term monogamous relationships.
The Whooping Crane is one of the rarest North American birds.
It is a long-legged, wading bird that is related to Rails, a group of small, secretive, marsh birds.
Adult birds are mostly white, with black extending the length of their outer wing feathers. Their crown is dark red, and a black 'moustache' extends from the bird's bill to the lower face. Their overall shape is reminiscent of a heron or egret, but more robust.
Never an abundant species, the total population had dwindled, due to hunting pressures and habitat loss, to a low of 16 birds in 1941.
Today, there are only thought to be 612 captive and wild birds in existence, although their numbers are increasing.
A team of researchers, led by the University of Georgia in Athens, tracked a group of endangered whooping cranes that was reintroduced to the eastern United States in 2001.
Each bird in this Wisconsin based population is fitted with a transmitter, allowing experts to track their movements.
As part of their courtship rituals, the cranes perform loud calls as well as jumping and flapping their wings.
Of the 58 breeding pairs monitored, 62 per cent began mixing with each other at least one year before they mated, according to reports in New Scientist.