Answers to Frequently Asked Questions
1) What is the average temperatures in Antarctica during the summer months when you do your reseach?
Average temperatures in summer and winter vary considerably in Antarctica. In the Antarctic Peninsula, where the climate is milder from its more northern position, the average summer temperature ranges from about 1° C to -4-5° C. The same is true in the Antarctic continent --most days the temperature ranges from 1° C to -2 or -3° C. Some days it gets REALLY warm at 3-4° C! The south pole is a different matter. Located on top of the polar plateau at the highest latitudes, summer temperatures there average around -30° C. That's pretty cold and I'm glad I don't have to work in those temperatures.
What really makes the difference here is the wind. If it's a calm day, once adapted to the climate down here, you can work outside comfortably in short sleeves even though the temperature is right around freezing. However, if the wind starts to pick up, the stronger it blows the colder it gets from the wind chill. Once it reaches 20-30 mph, it's difficult to work outside. So, daytime temperature doesn't really matter here that much--it's the wind that does it.
2) How can you distinguish between a male and a female penguin?
It is difficult to tell the sex of penguins from their external appearance, but it can be done if you know what to look for. For the Adélie penguin, you may be able to determine sex if the male and female are together at the nest. In that situation, the male is slightly larger, with a larger and deeper bill, relative to the female. The same is true for many of the other species of penguins as well. In addition, you can observe their behavior and sometimes tell sex. Male Adélie penguins arrive first at the colony in the late spring/early summer (they even return to the same nest site every year) to rebuild their pebble nest and call for their mate (they keep the same mate every year for life as well). When the female returns to the colony, she will go to her old nest site to find her mate and they can recognize each other by their calls. After the eggs are laid, the male usually takes the first incubation shift, which can range from 3-10 days or more, while the female returns to sea to feed and regain energy after producing the eggs. So, if you are watching all this at a colony, you can determine sex that way too.
3) Do penguins mate for life? What would a penguin do if something happened to its mate?
Adélie penguins begin breeding on average at age 5, though some may begin earlier or later. Once they have a mate that first year of breeding, they tend to keep that mate until it dies, disappears, or fails to return to the breeding colony one year. In some cases, a mate may be delayed in their return to the colony. In that situation, the remaining bird of the pair will find a new mate. They have to do this because if they wait too long to breed, their chick won't hatch in synchrony with all the other chicks and will be smaller and less likely to survive, especially during their first winter. The same thing happens if one of the mates dies--the other will have to find a new mate in order to reproduce that year. In this manner, the birds in a colony keep producing as many young as possible each year.
4) When do Adélie penguins mate and lay eggs?
Unlike some seabirds in more northern latitudes, especially those near the equator where the temperatures are about the same throughout the year, those found in polar regions have only one chance per year to breed. Penguins are no exception to this and in fact are under even more stress for breeding during a limited period because the Antarctic is so much colder than the Arctic. The summers here are relatively short and penguins have to reclaim their nesting territory, reconstruct their pebble nest, find their mate (or get a new mate), produce eggs, incubate those eggs, then raise the chicks. They have to do all this between November and February each year, though the amount of time available varies with latitude. The incubation period alone, for instance, takes about 35 days, and rearing the chick takes an additional 7-8 weeks (50-60 days). So there's not much time to do all this and at many colonies the males arrive and reclaim their nest sites by mid to late October.
5) Has global warming had an effect on the animals in Antarctica?
Yes, global warming is affecting Antarctic wildlife, but more so in some areas than others. For example, the Antarctic Peninsula is farther north than other regions of Antarctica and therefore has slightly milder temperatures. There, the warming trend has had the greatest impact: permanent ice shelves are breaking up at an alarming rate each summer, the average winter temperature has increased by 4-5° C over the past 20 years, and Adélie penguins have been declining in many areas. Because these penguins are dependent on sea ice as part of their habitat, (where they find and feed on krill) a decline in the amount of sea ice in the peninsula is affecting their populations. So, there has been a steady decline in this species in that area and, if the warming trend continues over the next 50-100 years, they could completely abandon the northern peninsular region. However, in the Ross Sea and other areas of the Antarctic farther to the south, the average temperatures are cold enough that the global warming has yet not had a significant impact on the wildlife. I n fact, Adélie penguins are increasing in east Antarctica and have been for the past 20-30 years. It would take much more warming than we have right now, I believe, to affect the species there. With the current trends in warming, though, it may be that not far in the future we will start to see more of an impact to wildlife in the deeper Antarctic.