The newly hatched fairy penguin. (Wildlife Conservation Society/Bronx Zoo)

For the first time in its 120-year history, the Bronx Zoo in New York has hatched a fairy penguin. In May, it welcomed the little fuzzball of a bird — just 25 grams when it was born, about the same heft as a AA battery — into its flock.

The bird is too young to have its sex identified. (It is not possible to simply flip over a juvenile penguin and get an answer, as the birds do not display obvious external anatomy. Time — more specifically later behavioral or chromosomal testing — will tell.) But by late July the animal was big enough to be added to the colony of fairy penguins on display at the zoo.

Fairy penguins, also known as little penguins or blue penguins, grow rapidly. When the penguin was filmed being weighed a few days after hatching, trembling with all the 72-hour-old strength it could muster, one of the zoo staff members exclaimed, “Oh, my God, you’re huge!” It appeared to have almost doubled in weight, to about 44.5 grams.

Little penguin is an apt moniker. Of the 18 penguin species, these penguins are the smallest. They grow to only about 13 inches tall, and are no heavier than 3 pounds as adults.

The other fairy penguins in the Bronx Zoo arrived from Australia, as part of an international breeding program. All of those birds were born at the Taronga Zoo in Sydney. They are chatty, social animals that eat squid, fish and other smallish sea life. During breeding season, the birds will dig burrows in the sand to lay their eggs.

Such breeding programs are designed to create a healthy genetic stock for fairy penguin conservation. Although the International Union for the Conservation of Nature lists the species as “least concern,” the fairy penguin population is declining. Coastal oil spills, habitat degradation and feral cats all pose threats to the birds. There are even reports of crayfish hunters who poached the penguins to use the bird meat as bait in the 1980s and 1990s, although the lasting impact on fairy penguin populations is not clear.

The fairy penguin will not go down without a global push. In addition to the penguins in the Bronx, another breeding colony lives at an aquarium in Boston. In Australia, two dozen captive-bred penguins were released into the wild in 2007.

In some places, help for the penguins has taken unusual forms.

When foxes appeared on an island near Victoria in Australia about a decade ago, the penguins took a hit. “We went from a point where we had around 800 penguins down to where we could only find four,” Peter Abbott of the Penguin Preservation Project told the BBC in late 2015. To protect the penguins from the foxes, the group trained a handful of guard dogs.

Although the premise sounds like “Babe” by way of “Happy Feet” — it inspired a movie named “Oddball,” after one of the dogs — the program was a success, according to Abbott. The fairy penguin population rebounded to about 200 birds.

The juvenile fairy penguin, in the exhibit in July. (The Wildlife Conservation Society/Bronx Zoo)

And in the Flea Bay of New Zealand, a blind fairy penguin named Blindy has found a pair of caretakers in Shireen and Francis Helps. Subjects of a recent profile by the Associated Press, the Helpses have been caring for penguins since 1974. Blindy is something of a special case. Shireen Helps will toss the critter into a pond so it can safely swim away from the sides.

“If it gets dizzy going around one way, it changes direction and goes around the other way,” she said to AP. “So it’s really learning very well.”