You won’t find them waddling down Market Street this Sunday, but a pair of male Magellanic penguins at the San Francisco Zoo are already standing up for Pride this month in their own special way.

The duo, Eduardo and Rio, serve as surrogate daddies in one of the most successful breeding programs for the species of penguins in the world. The pair have become so good at their duties, they’ve become the go-to couple for raising penguin chicks at the zoo, according to Anthony Augello, the SF Zoo’s Assistant Curator of Birds and Reptiles.

“Anytime we have an egg that’s really valuable for the species survival plan, we automatically put it with our foster same-sex couple,” Augello told KPIX-TV, “because they’re fantastic parents.”

The pair is known for building some of the best nests in the colony, and giving some of the best care and attention to both eggs and chicks. More so, it seems, than many of the opposite-sex penguin couples at the zoo. The pair have raised four penguin chicks over the last three years, with their current adopted chick currently in what the zoo calls “finishing school.” It will take part in the zoo’s “March of the Penguins” with other chicks in July.

Magellanic penguins, as the name implies, inhabit the area around the Strait of Magellan, rather than the chilly lands of Antarctica that many associate with the species. As a result, the climate of San Francisco proves ideal for these flightless birds. Read more via LGBTQ Nation