Bald head and piercing stare aside, Harold the griffon vulture is quite an odd bird.
The scavenger made headlines worldwide last week after laying an egg in her enclosure at the Eagle Heights Wildlife Foundation in Kent, England. The noteworthy element is that Harold, a resident of the organization’s sanctuary since it opened its doors 20 years ago, was thought to a male this whole time.
Unlike many bird species, male and female griffon vultures look completely identical – determining the sex of an individual actually requires a DNA test. When Eagle Heights acquired Harold back in the '90s, they were told (s)he was a male based on the results of one such test, performed on her when she was a chick.
In the ensuing years, no one had cause to suspect otherwise, until last Thursday:
“BREAKING NEWS, Today Eagle Heights staff are FLABAGASTED!!!(sic)” a Facebook post exclaimed. “20 years ago we bought HAROLD our MALE Griffon Vulture only to find this morning that he is actually a SHE and has laid her 1st ever egg!!!"
A popular fixture of the wildlife park’s birds of prey exhibit, Harold had been housed alongside the other birds in the main mews until last fall, when keepers decided to let her spend the winter cozied up in an aviary.
Similar to chickens, female vultures will lay unfertilized eggs in the absence of a mate--but only in the right conditions. Jemima Parry-Jones MBE, director of the International Centre for Birds of Prey, told IFLScience: “stressed birds are unlikely to lay either in captivity or in the wild.”
Apparently, the new-found privacy inspired Harold to lay for the very first time.
After recovering from their initial shock, Eagle Heights now hope to begin captive breeding efforts by finding her a mate.