In sea mariner lore, an albatross is considered a good omen, and for almost seven decades, one bird has spread generations of blessings across the Pacific Ocean.

Wisdom, a 68-year-old Laysan albatross believed to be the world’s oldest known wild bird, has returned to her home at the Midway Atoll national wildlife refuge for yet another winter – and laid yet another egg to add to the already impressive brood that she has built up over an impressive lifetime.

Biologists with the US Fish and Wildlife Service think the almost-septuagenarian has birthed and raised as many as 36 chicks over the years. Should her latest egg with her longtime lover, Akeakamai, hatch, fledge and take to the open sea, it will be her 37th.

Wisdom was first banded in 1956 by biologist Chandler Robbins, who estimated that she was about five years old at the time. The biologist and bird met again in 2002 when he went to band her and recognized that she had been one of the 8,400 birds he recorded during his first season, 46 years previously.

Albatrosses are known for their long life spans and often outlive their researchers – Robbins died in 2017 at the age 98 – but what makes Wisdom unique is that researchers have been able to monitor her habits for so long. She may or may not be the oldest wild bird, but she is the oldest known wild bird, and her habits have been lovingly documented by the fish and wildlife service over social media.

Oceanographer Dr Sylvia Earle, and Wisdom, the oldest known living Laysan albatross, at Midway Atoll national wildlife refuge. Photograph: Susan Middleton/USFWS - Pacific Region

And because so much of her background and history is known, researchers are learning more about her species by observing her. To a human, 68 years old may seem preposterous to still be laying eggs, but Wisdom and the other few documented examples of albatrosses in their 50s and 60s who do not appear to have trouble breeding at that age show the situation may be different for birds, said Beth Flint, a USFWS wildlife biologist.

Like many albatrosses, Wisdom returns nearly every year to the place she was born for nesting and mating. Midway Atoll, a two-and-a-half-sq-mile island belonging to the US that was the site of the decisive Battle of Midway during the second world war, remains mostly uninhabited when it comes to humans. But come winter, more than 1m Laysan albatrosses flock to the beaches to nest.

Albatrosses spend 90% of their lives at sea, soaring over the northern Pacific Ocean and feeding on squid and fish eggs. The fish and wildlife service estimates that Wisdom has clocked more than 6m miles in her travels – according to the Cornell lab of ornithology, Laysan albatrosses can range anywhere from the Aleutian Islands and the southern Bering Sea to Costa Rica.

Albatrosses take mating and nesting seriously, forming bonds with their mates for life. The Cornell lab describes their courtship displays as elaborate; they include “coordinated movements in which the birds touch bills, spread one or both wings, bob their heads, place their bill under one wing, and pause with their bill pointed at the sky”.

Once they’ve met their mates, the birds will rendezvous at the same nest site every winter – and go through some iteration of the courtship process again, Flint said.

“There is preening and a dance,” she said. “They’re very tactile animals. They sit closely and preen each other and snuggle. We can’t know what they’re feeling, but they exhibit the kind of behaviors that reinforce a bond and a connection.”

Researchers first noted Wisdom’s relationship with Akeakamai in 2006 and are unsure if she had other mates before Akeakamai. But albatrosses are believers in co-parenting, and will take turns incubating an egg, caring for the chick and foraging for food over the ocean. Should this egg survive, Wisdom and Akeakamai will spend about seven months on Midway Atoll incubating and raising their chick.

Albatrosses lay only one egg a year, and because it’s such a lengthy and energy-consuming process to both incubate and raise a healthy chick, most do not do it annually. While researchers are still collecting data regarding the frequency at which Laysan albatrosses breed, Wisdom “does seem to be exceptional in that she has bred for a number of years consecutively and has not taken a break”, Flint said.

Wisdom, a 68-year-old Laysan albatross, protects her egg. Photograph: USFWS - Pacific Region

Wisdom has managed to raise a number of chicks who have gone on to raise chicks of their own, she has also faced hardship. In 2015, her egg was reported missing, which biologists say is just what happens sometimes.

But her fertile contributions to the continuation of her species make every homecoming a celebration for scientists. Last year, they observed a chick that she fledged in 2001 setting up a nest just a few feet away. It was the first time one of her chicks had been documented returning to nest.

“Midway Atoll’s habitat doesn’t just contain millions of birds, it contains countless generations and families of albatrosses,” Kelly Goodale, a fish and wildlife service refuge biologist, said in a blogpost. “If you can imagine when Wisdom returns home, she is likely surrounded by what were once her chicks and potentially their chicks.”