Archive for April 2013
Penguins have been called many things over the centuries. Maori named the Yellow-eyed Penguin of New Zealand the Hoiho, which means “noisemaker” in reference to its loud call. Aboriginal Australians named the Little Blue Penguin “gur-roo-mul”. In Swahili, a penguin might be called “ndege ya nchi za baridi” meaning “big cold country bird”. This last version gave rise to the scientific name Dege hendeyi for one of South Africa’s four Pliocene fossil penguin species. Besides having lots of different names, there has been historical confusion over the word “penguin” itself, and it has been applied both to true penguin and to the recently extinct Great Auk in historical accounts.
One name that historians of ornithology seem to have overlooked until recently is “woggin”. This name appears in many whaler’s writings during the 1700s and 1800s, and is variously spelled wogæn, waggin, wargan, wargin, waugin, wogen, woggin, woging, woglin, or yawgin. In 2007, Storrs Olson and Judith Lund published a paper cataloging the various records of this name. It appears to have been applied to penguins and auks, and it is not too surprising that sailors might confuse two types of black and white feathered, flippered, flightless diving birds. Apparently the word fell out of favor by the era of the Civil War and was until now lost to history. By checking the geographical coordinates associated with each use of “woggin” (usually readily available in ship’s records), the authors were able to pinpoint which references applied to Great Auks, which only occurred in the Northern Hemisphere, and which applied to penguins (which live in the Southern Hemisphere, aside from the equatorial Galapagos Penguin).
Why should we care? Beyond helping us interpret historical records, uncovering the word woggin can help us understand extinct birds. Luckily, no penguins have gone extinct since the whaling era, but the Great Auk was tragically wiped out by humans in the 1840s or 1850s. We know very little about this bird because few ornithologists conducted studies while it was still alive. Most human encounters therefor took place when the auks were on shore nesting in North Atlantic islands. However, during the rest of the year Great Auks appear to have roamed far and wide in the ocean. For example, a sailor’s log from the sloop Sandwich reports that on May 10th 1762, “wogæns” were sighted off the outer banks of North Carolina. Such records can help us recreate migration patterns and shed more light on this remarkable vanished bird’s ecology.
Beane, J. F. 1905. From forecastle to cabin. New York: The Editor Publishing Co.
Olson, S.L. and J.N. Lund. 2007. Whalers and woggins: a new vocabulary for interpreting some early accounts of the great auk and penguins. Archives of Natural History 34: 69-78.
Last post we talked about how most penguins prefer isolated island habitats. Well, if you have ever visited Cape Town you may have seen plenty of penguins on the mainland, at colonies like Boulders Beach. Why aren’t land predators chasing them off? One of the reasons penguins do so well here is people have given them a helping hand by setting up a nearly perfect environment. At Boulders Beach, there is a plastic penguin colony set up, in the form of dozens of partially buried heavy-duty plastic pots. Each of these houses a penguin – they serve as little penguin bungalows in place of the usual rock and dirt burrows the birds would otherwise seek out. Fences keep people from bothering the resting penguins and discourage predators – the only other vertebrate I saw hanging out in the nesting area on my visit was a harmless hyrax.
As we discussed last post, penguins were very diverse in Africa in the past. We have two good geological time slices, one from the Miocene and one from the Pliocene. At both times, there were four different species inhabiting the southern coast. Today, there is only one. This raises the question: what happened to all those extinct species? It might seem natural to point the finger at humans, since we have been involved in the extinction of many flightless birds such as the Dodo, Moa, and Great Auk. In this case, the fossil record seems to exonerate us. By the time the first human settlers arrive in South Africa, all of the extinct species had already vanished and only the modern Black-footed Penguin was hanging around. Archeological sites show no evidence of early humans roasting up big piles of penguins at campsites, suggesting that overhunting had no role in the extinctions.
A more plausible explanation involves sea level change. Penguins love islands. This is because the land is actually a dangerous place for penguins. Predators like stoats, cats, dogs and even large birds pose a big danger, especially to hatchlings and eggs. This is one of the reasons why penguins tend to breed in isolated places, where there are likely to be few land mammals to harass them. Today, it is possible to see Black-footed Penguins nesting in places like Boulders Beach on the coast near Cape Town. However, the majority of the regional population nest on small offshore islands, where they are safer from land predators.
Over the past 12 million years, sea level along the African coast has ramped up and plunged down like a slow-motion roller coaster. During the time the fossil species lived, there were far more islands in the area. This is because higher sea levels swamped the coast, submerging many low-lying areas and turning hilltops into islands. These areas would have been prime penguin real estate. As sea level dropped towards the present, the islands would have been reconnected to the mainland, allowing terrestrial predators to invade. We suspect this could have removed much of the suitable nesting colony areas, resulting in a lower carrying capacity for penguins and the extinction of some species.
Roberts, D. L. et al. 2011 Regional and global context of the Late Cenozoic Langebaanweg (LBW) palaeontological site: west coast of South Africa. Earth Sci. Rev. 106, 191 – 214.