Until the African penguin starts observing federal holidays, Sparks Perkins won’t either.

Which is to say the morning of Dec. 25 will bring not presents and mistletoe for the 33-year-old San Franciscan, but beak trims and fish guts.

A biologist at the California Academy of Sciences’s Steinhart Aquarium, Mr. Perkins belongs to that unfaltering set — hospital personnel, firefighters, point guards — whose work pauses for no holiday. Call him essential avian personnel, tethered to the needs of the resident 50 or so birds. Weekends, late nights: All fair game for whatever emergencies arise among Mr. Perkins’s flock.

“I’ve worked six of the last 10 Christmases,” he said. “That’s just the price of getting to work with these animals.”

Mr. Perkins describes that work as entering a daily soap opera. This bird wakes up grouchy, that one sassy. Keys get stolen from belts. That famed penguin monogamy relaxes a bit.

“Some have wandering eyes. They’ll wander off for a little fling and then come right back,” Mr. Perkins said.

Occasionally, they switch teams entirely. A while back, a couple male Magellanic penguins from Brazil pair-bonded out of the blue.

“Those boys made the most fabulous nest,” Mr. Perkins recalled. “I remember they were the best interior designers.”

A native of Mississippi, Mr. Perkins has loved birds since the age of 3, when his parents gave him his first parakeet. Macaws, lovebirds and ornamental pigeons followed. Some nights brought 4 a.m. trips to the post office, to pick up a cart of pheasants he’d ordered.

“I was a very different 14-year-old boy,” he said. “Instead of playing soccer after school, I’d go to the aviaries I built. I had about 70 birds.”

The Academy’s own collection grew recently, with the arrival of two African penguin hatchlings. Given the institution’s role in preserving endangered species — Mr. Perkins just returned from a conservation project in South Africa — helping these birds thrive has been paramount. Every morning, Mr. Perkins lifts each chick from its nesting box, places it on a tiny scale and logs an adorable number of grams. Putting on weight over the holidays is encouraged here.

Penguins possess a quiet if teetering dignity. Penguin chicks possess none. They are chubby orbs of fluff, inept, can’t even be trusted in water. Until that down is replaced by juvenile plumage, they’d sink like sweet little stones. But in captivity, they can live some 30 years, as much as twice their life span in the wild. They do need stimulation to keep them happy and healthy, and the biologists here break out laser pointers, blow bubbles and play colony sounds over an iPad.

The birds are also enriched by the sight of visitors watching them. At the height of the pandemic, with nobody on the other side of the glass, staff did yoga for the animals.

This Christmas, Mr. Perkins and his colleagues will find little ways to make the day special, while the birds squawk about as usual. They’re not turtle doves or partridges in a pear tree, but they’re family.