It is a long-established Antarctic fact that the southernmost penguin colony on the planet is at Cape Royds, on the west side of Ross Island, near McMurdo Station and Scott Base. Slightly anomalously, this is an Adélie penguin colony, being a few minutes further south than the ‘southernmost’ emperor penguin colony at Cape Crozier on the opposite side of Ross Island. It is unclear when the ‘southernmost’ claim was first made for Cape Royds, but the earliest reference that I have found is a 1968 scientific paper by Dietland Müller-Schwartz.
Before leaving Punta Arenas, I checked the latitudes of both Cape Royds and Cape Crozier, so that I could mention how much further north the Gould Bay emperor penguin colony is in my lectures. Gould Bay, on the northern edge of Berkner Island in the Weddell Sea (east of the Antarctic Peninsula) is where ANI establishes a field camp in November-December each year, and provides guests the opportunity to camp overnight within 1-3 km of an emperor penguin colony. I was very surprised to discover that Gould Bay was apparently further south than both Cape Crozier and Cape Royds, and so I set out to check and confirm details about each site.
Adélie penguins require sites free of ice and snow to breed, building raised nests out of small stones that they invest much energy in collecting and stealing. Ice-free sites are rare in Antarctica. For this reason, Adélie penguin colonies are typically at the same site year after year, and carbon-dating of fossilised guano deposits has revealed that some colonies have been in the same location for tens of thousands of years. The Adélie penguin colony at Cape Royds is situated close to the historic 1908 Shackleton ‘Nimrod’ hut at decimal latitude 77.55 degrees south, 10 km further south than the emperor penguin colony at Cape Crozier (decimal latitude 77.46 degrees south).
In contrast, emperor penguins typically breed on fast ice or shelf ice (i.e. ice attached to the Antarctic mainland, but with seawater underneath – fast ice is frozen seawater, while shelf ice is formed where a glacier flows out beyond the coastline). Emperor penguins are the only birds that (with a few minor exceptions) do not breed on land – adult males incubate the single egg on the top of their feet, while standing on ice. This means that colonies can shift location both within and between breeding seasons, as the birds (which can move slowly while balancing the egg or small chick on their feet) seek shelter from strong winds, or locations more readily accessed from open water (i.e. their feeding grounds). Each of the c.45 emperor penguin colonies scattered around the Antarctic continent is typically in the same general location each year, but may move a few hundred metres or a few kilometers between seasons. The Cape Crozier emperor penguin colony has been relatively stable in location over time. It was the focus of the epic ‘Worst Journey in the World’ in June 1911, when Edward Wilson, Henry (Birdie) Bowers and Apsley Cherry-Garrard set out from Cape Evans to collect recently laid emperor penguin eggs for embryological study. This was only 9 months before Wilson and Bowers perished with Robert Falcon Scott on their return from the South Pole, after having been pipped at the post by Roald Amundsen and his companions.
The Gould Bay emperor penguin colony was rediscovered about 8 years ago, and was stable in location from 2006 till 2013. Following a large break-out of sea-ice in February 2014, the colony moved about 6 km south, to where the break-out edge was before the sea refroze this past winter. The ANI staff who set up the Gould Bay ‘Emps camp’ in November 2014 confirmed the southern edge of the colony to be at decimal latitude 77.78 degrees south. This is 26 km closer to the South Pole than Cape Royds and 36 km further ‘south’ than Cape Crozier.
Information on the location of the Gould Bay emperor penguin colony was included in a 2010 paper in the Proceedings of the Linnean Society, which tabulated locations and sizes for all 46 known emperor penguin colonies, as detected by satellite imagery, and put Gould Bay at 77.71 degrees south, with Cape Crozier the second-to-southernmost colony.
The erroneous ‘southernmost penguin colony’ claim for Cape Royds has continued to be made frequently since the 2010 PLoS paper. I found 16 recent examples in a quick search, along with a couple of examples of Cape Crozier being described as the southernmost emperor penguin colony. I am uncertain why the Cape Royds myth is so persistent. Perhaps it has something to do with the Ross-Sea-centric view of Antarctica evident in United States and New Zealand culture and literature. The Ross Sea is the largest and southernmost indentation in the roughly circular Antarctic coastline, but much of the south of the embayment is filled with high shelf ice (the Great Ice Barrier), with the ice cliffs forming an impenetrable barrier to penguins. It may never have occurred to those writing about the sacred sites of Cape Royds and Cape Crozier that penguins may be able to access breeding sites further south elsewhere around the continent, despite breeding colony co-ordinates falsifying the Cape Royds (and Cape Crozier) claim having been in the public domain for at least the past four years.
Te Papa vertebrate curator Dr Colin Miskelly visited Antarctica during November-December 2014 as a guest lecturer for Adventure Network International (ANI). This is the fourth in a series of blogs based on his experiences in Antarctica, and particularly at the Gould Bay emperor penguin colony in the southern Weddell Sea.
Previous blogs in this series:
Subsequent blogs in this series:
See also the Te Papa blogs about the emperor penguin that came ashore near Wellington in June 2011:
[links to the eleven subsequent global penguin blogs are found at the bottom of this first blog]