Flamingo foster fathers hatch an egg together at the San Diego zoo

Two male flamingos have joined their kind’s ranks of same-sex co-parents after hatching an egg together at the San Diego Zoo Safari Park.

The two foster dads are both in their 40s and are lesser flamingos, a species found in sub-Saharan Africa and western India, according to the zoo. The chick is also a lesser flamingo.

They were given a fake egg to sit on earlier this year – and after passing the test, they were given a real egg, which they hatched successfully.

“The pair has perfected their fatherly duties by alternating brooding responsibilities”, the zoo wrote in a social media post.

A two-dad flamingo family is not unprecedented. Earlier this year, two male flamingos at a UK zoo, Curtis and Arthur, successfully hatched a chick.

The San Diego foster parent flamingos feed their chick crop “milk” from their upper digestive tract. “Both males and females can feed the chick this way, and even flamingos that are not the parents can act as foster-feeders,” the zoo said.

The public occasionally becomes fascinated with stories of relatively uncommon bird hatchings.

An eagle at a Missouri bird sanctuary went viral after he tried to hatch a rock.

In 2017, two male griffon vultures successfully hatched an abandoned egg at Artis Amsterdam Royal Zoo.

Two years ago, a same-sex male Humboldt penguin couple at a New York state zoo hatched an egg, which had been glued together after the breeding pair, Poquita and Vente, cracked it and gave it to the male penguins. The male penguins, Elmer and Lima, had also been given a dummy egg to practice sitting on before they hatched their real one.

“It takes practice,” said zoo director Ted Fox, noting that some couples’ fight for who is going to sit on it and when. “That’s how we evaluate who will be good foster parents – and Elmer and Lima were exemplary in every aspect of egg care.”