Roger Williams

Three Humboldt penguin chicks hatched at the Roger Williams Park Zoo in April.

The chicks required hand-feeding and around-the-clock care from the zoo's staff.

Humboldt penguins are a vulnerable species, and the zoo is part of a conservation effort.

Roger Williams Park Zoo has three fuzzy, new residents.

"We are delighted to share that three Humboldt penguin chicks successfully hatched this April," the zoo said in a Facebook post on Monday, June 15.

Penguins returned to the zoo last year for the first time since 2013 when the zoo brought in 12 Humboldt penguins from several different zoos and put them in a new, $1.5 million exhibit. At the time, zookeepers expressed hope that the penguins would reproduce.

"Every new chick is a victory for this vulnerable species, but this trio required a true team effort," the zoo said in its Facebook post. "Shortly after hatching, our dedicated animal care and veterinary teams realized the chicks needed some extra assistance. They immediately stepped in to provide around-the-clock care and hand-feed the newborns, ensuring they received proper nutrition during their most critical milestones. We are happy to report that their health improved greatly with this specialized care!"

Zoo visitors won't be able to see the chicks immediately, according to the post.

"As they molt out of their 'fuzzy baby britches' and into smooth juvenile tuxedo feathers, they are continuing to bond with their care team who will support them through swim school, then re-introduce them to the rest of their friends and family," the zoo said. "Once they are cleared as expert swimmers, they will make their official public debut. For now, keep following along on our social media channels for updates!"

Humboldt penguins are listed as "vulnerable" by the International Union for Conservation of Nature with an estimated 12,000 breeding pairs in the wild. The zoo says it's committed to the long-term viability of the species through its involvement in the Species Survival Plan.

The 12 Humboldt penguins that moved into the zoo this spring include eight males and four females from six different zoos.

While penguins are often associated with the cold of Antarctica, Humboldt penguins live on the coast of Peru and Chile, where "it's actually pretty temperate," zoo director Stacey Johnson said previously. "This is the kind of climate they live in."

"Our challenge with managing penguins isn't going to be to keep them cold enough," Johnson said. "It's actually going to be to keep them warm and comfortable enough."

Adult Humboldt penguins stand 15 to 18 inches tall and weigh about 9 pounds.

Their home, a former seal exhibit, includes indoor and outdoor space, a swimming area and a rocky beach because their feet stay healthier when they walk on rocks. The City of Providence provided a $1.5 million grant for the penguin exhibit.

Humboldt penguins are typically monogamous and mate for life.