On Humble Island, Adélies rest as they incubate their eggs. Most pairs produce two eggs per season. This incubation in early- to mid-December is the quietest time in the Adélie colonies, as the penguins take turns incubating the eggs and foraging at sea.

The end of Colony 23, one of many that has disappeared as Adélie populations around Palmer Station have declined from roughly 35,000 breeding pairs in 1975 to 5,400 today.

A brown skua sits on the edge of Colony 23 on Torgersen Island, ready to eat the eggs of the last remaining incubating Adélie. The colony disappeared in December 2005.

An Adélie egg eaten by brown skuas. Such predation is common and not harmful to robust Adélie populations. But as the Adélies have steadily disappeared around Palmer Station due to rising temperatures, skua predation often pushes the shrunken colonies into oblivion.

A South Polar skua, one of two major skua species found in the vicinity of Palmer Station. Farther south in Antarctica, South Polar skuas are the main terrestrial predators of Adélie penguins, but around Palmer Station, the larger brown skuas are the primary predators of Adélie penguins. An aluminum leg band, used by Fraser to identify the skuas, is on the bird’s right leg.

A southern giant petrel, with a satellite transmitter on its back. Fraser and his wife, Donna Patterson, have done groundbreaking studies on southern giant petrels and use the data from the satellite transmitters to determine where the large seabirds forage in the Southern Ocean.

An iceberg near Palmer Station in late December, after the sea ice had been banished for good.

With Jen Bloom at the helm, the team’s lead boat makes its way through the sea ice to Torgersen Island.

One of the spectacular icebergs that filled the waters of the Southern Ocean off Palmer Station. The striking blue hue comes from the weight of ice squeezing the oxygen bubbles out of glacial ice during the course of centuries, which alters the ice’s color, giving it the otherworldly shade.

While the birding team’s rubber Zodiac boat was tied up on Christine Island, an Adélie leapt into it before we shooed it back into the sea.

An Adélie pair greets each other with a so-called “loud mutual display” as the penguin on the right, just in from the sea, prepares to take over the incubation shift.

The continuing presence of sea ice kept Fraser’s birding team away from the penguin islands, forcing the team in December to don orange waterproof suits and push its way through the ice to Torgersen Island. Looming over the team is a remaining finger of ice from a decaying iceberg.

Sunlight streams through an iceberg. Palmer Station residents were fond of picking up chunks of glacial ice from the sea and hauling them back to the station, where they were broken up and used in mixed drinks.

A typical scene that warm, still December, with “brash ice” from calving glaciers in the center of the picture and the peninsular range in the background.

A pair of leopard seals resting on rafts of ice.

A small leopard seal. Much larger leopard seals, some a dozen feet long, patrolled the waters around Palmer Station, gorging on Adélie penguins.

A large tabular iceberg sits off Dream Island. At left, on the rocky peninsular, two of Fraser’s team members are barely visible.