The spirit of adventure, under many guises, is what lures most people to Antarctica. Apart from tourism and industrial fishing, including whaling and sealing, commercial attractions are few and, in the case of mineral exploitation, only figments of the imagination at present. Crew members aboard ships might well have preferred to be any place but the Southern Ocean, yet the impetus behind such voyages stemmed from someone’s appetite for adventure and discovery.

For me, Antarctica was a place to define myself against the life-defying forces of nature that are so evident there and known in the temperate zone only among...

Penguins are the most specialized and most capable divers among birds. Much of the foraging behavior of penguins has been studied, especially by biologists using instruments and apparatus developed to quantify aspects of diving, swimming, prey capture, and energetics. More than specialized divers, however, penguins truly are marine creatures, perhaps more so than any other group of birds. Therefore, to understand the Adélie penguin’s behaviors at sea, where it spends more than 90 percent of its total life,¹ more than just a description of prey searching and capture is needed.

To understand the marine ecology of a penguin one must...

The Adélie penguin world population numbers about 2.5 million breeding pairs, which makes this species an abundant seabird. However, it is by no means the most populous seabird species or even the most abundant penguin. More abundant are the macaroni penguin (Eudyptes chrysolophus, 11.8 million pairs), chinstrap penguin (7.5 million), and rockhopper penguin (Eudyptes chrysocome, 3.7 million).⁵⁶

Adélie penguins nest at sites distributed around the coast of Antarctica, as well as on coasts of islands located at varying distances away from the continent (fig. 3.1). For instance, they nest in the Balleny and South Shetland island groups (110-200 kilometers off...

The annual cycle of an Adélie penguin includes a premigratory period of feeding and fattening, spring migration to the colony, nesting, fall migration from the colony, continued heavy feeding, and then molt. All this takes about six to seven months; the remaining months—fall and winter—are ones of little activity. The subject of wintering was considered in chapter 2, and nesting is taken up in greater detail in chapters 5 and 6. In this chapter we consider the annual cycle, the timing of its various parts, and molt in some detail. As we shall see, the central part of...

Chapter 4 described the timing of various phases of the Adélie penguin’s annual cycle. The beginning of the nesting cycle—migration to and arrival at the colony—was looked at in detail, as was time spent in the colony and the end of the nesting cycle, the molt. This chapter describes the major events of the occupation period. Included are age of first breeding; territories, nests, and nest building; pair formation; egg laying, eggs, and clutch size; and incubation and hatching success.

In a study at Cape Crozier, the modal age of first breeding was five to six years (table...

Adults who lose their eggs return to reoccupy their nest sites at about the time that eggs successfully incubated by other pairs begin to hatch, hence the name reoccupation period for this phase of the breeding cycle.⁴⁹ Breeders who failed early in the breeding process will remain for a few weeks. Coincidentally, young nonbreeders begin to visit in a sequence structured by age: younger ones arrive the latest and stay the shortest amount of time. These birds are actually accomplishing their first occupation rather than reoccupying the colony. Many are returning for the first time since they fledged two to...

Most of the smaller seabird species, such as storm petrels, diving petrels, auklets, and murrelets, often are preyed on by certain larger birds, such as frigatebirds, gulls, skuas, eagles, and falcons. Unlike the adults of most large-bodied seabirds, therefore, these smaller seabirds are not at the apex of the food web. In response to such predation, these smaller seabirds have acquired activity patterns that bring them to breeding colonies only during the night. In the very highest latitudes, where it is daylight twentyfour hours per day during summer, few of these smaller species nest. At the locations where most nest,...

The number of chicks produced per breeding pair is known in demographic analyses as fecundity. As we have seen in earlier chapters, the number of chicks fledged is affected strongly by factors at play in the colony, such as parental age, nest location, and timing of breeding. The number of chicks fledged is also strongly affected by parents’ success at obtaining food. Along with fecundity, other important demographic variables are breeding propensity, or the proportion of the population that attempts to breed among those physiologically capable of doing so; age at first breeding, which indirectly defines physiological capability; and annual...

The world’s climate is changing, as it always has, but the rate of change is accelerating at an unprecedented rate, at least in the context of the last few thousands or tens of thousands of years.²⁴ More and more often, we read articles or hear stories in the news about global warming. Most climate researchers agree that Earth’s surface air temperatures are warming at a rapid rate. Questions abound, and the answers reflect profound differences of opinion. Is the rate of change understandable as we continue to move away from the period of the Last Glacial Maximum (LGM)? If not,...