When zookeepers at the Artis Zoo in Amsterdam found an abandoned fertile egg at the bottom of the griffon vulture aviary several months ago, they weren’t quite sure what to do. They believed that the egg must have been unclaimed by a female vulture who had not yet found a permanent mate, since the birds practice monogamy, but they weren’t sure whose it was or if someone else would take it.
They first tried giving the egg to the other heterosexual couples that were already formed in the aviary, but none of them would adopt it. They then put the egg in an incubator for the time being and brainstormed about what to do.
The Artis Zoo has a homosexual vulture couple featuring two males that have bonded, nested, and mated together for several years now. Since they are monogamous creatures, it’s likely that they will stay together for the majority of their life, but since homosexual couples in the wild have not been observed because males and females look too similar, this is unclear. Females are the only ones able to lay eggs, so although the males attempted to mate, they were of course never able to produce any eggs.
“We put our heads together and we thought this was the ultimate chance for our male couple to have a fertile egg. They have a perfect opportunity to raise a chick,” zookeeper Job van Tol told TIME. “It’s risky and a bit nerve-wracking because you don’t have any promises that they would understand how to raise a chick.”
Zookeepers placed the egg in the males’ nest and, much to their surprise and delight, the males immediately accepted the egg as their own and took turns sitting on it. That was over four months ago; in May, van Tol said he had climbed up to the nest and was shocked at what he saw.
“I saw this little moving baby chick,” he said, adding that he signaled for another caretaker to come watch the young family in action. “It was a special moment. We fell into each other’s arms, which we never do. This we just couldn’t believe.”
The chick has been growing like crazy and van Tol said the two dads are amazing and take turns doing everything, from guarding the nest to foraging for food. He likened vultures to that of penguins, who share parental duties in every aspect except for the laying of eggs and also said that their amazing qualities as parents have been known for a very long time. The Ancient Egyptians even looked to vultures as a symbol of femininity because of their universally maternal nature.
This is the first hatching that the zoo has had in 5 years, and the chick was hatched around the same time that another one was by two heterosexual parents that were recently rescued. This is also the first time that gay griffon vultures have hatched an egg together in a zoo, although it is not the first attempt. Last year, the Nordhorn Zoo in northern Germany gave a gay couple an abandoned egg that wound up not hatching. When the zookeepers finally tried to separate the egg from the couple, the vultures became very aggressive and were protective over what was supposed to be their baby.
Since they are such good parents, whether they’re male or female, vulture expert Dr. Corinne Kendall said that it makes sense that these vultures would excel at their new job.
“Given the chance, it makes sense that two males could take care of an egg,” she said. “Beyond laying it, they are capable of all the other steps.”