Here is the second set of questions/answers from Spring Hunter's class at Murray Middle School, received on 3 February 2003:

1. You have mentioned that penguins are mates for life.  What would a penguin do if something happened to its mate?

A penguin begins 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.

2. About how long would a colony stay at one site before abandoning the site?

This is a good question and there is no general rule or answer.  From long-term observations at many active colonies, we've found that some will be abandoned relatively quickly, within decades to a few years from when the observations began.  The reasons for this are varied--it may be that few or no chicks are surviving from that colony anymore (either from excess predation by skuas or other birds, or from a change in local food supplies).  If so, there would be no chicks returning to the colony to breed as adults in future years and as the adults that are in the colony die off, the colony shrinks and then disappears.  A colony also might be abandoned quickly if the weather patterns change and the colony area becomes covered with snow late into the summer. In this case, the penguins might still try to nest there, building pebble nests on the snow, but with later melting the nest, with eggs and/or chicks, would fall apart and be lost.  So, the adults would have to abandon this site and breed elsewhere if they want to be successful.  Many large colonies, though, may have been occupied for hundreds to thousands of years so abandonment there might take a long time. 

3. Approximately how long does it take you to get your test results and exactly what is the testing process?

The main test I need to complete with my samples is radiocarbon dating.  This process takes a long time because each sample I submit, either a piece of bone, tissue, or eggshell (it has to be organic), must be chemically treated to clean it of impurities that might affect the results.  The specimen is placed in acid treatments and dissolved until only a small amount of the original organic matter, and no intrusive particles, remains.  This organic matter contains amino acids from the once living organism.  A small pellet is formed from this matter and placed in a mass spectrometer, an expensive piece of equipment that only a few labs have (it can cost $1 million or more!) where over a period of hours the carbon isotopes are measured.  Without getting too complicated here, the measurements provide an indication of the age of the specimen because, after a living organism dies, the carbon isotopes start to decay or change. The measurements tell us how long that decay process has been going on, thus giving the age of the specimen or the number of years ago when it died.  It takes 1-2 months to get this work done because the labs have lots of other work to do and the chemical processing takes time too.

4. Is there a specific mating season for penguins or does this happen year round?

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,  Are you pleased with your research findings so far?

Definitely!  We've sampled more sites so far (14) than I can usually do in one season. The reason for this is first, there are more abandoned colonies in this area than I've seen anywhere else in Antarctica, and second, the summer here has been very mild making it easier to get lots of field work done.  So, we've been out in the field every week, there are lots of sites to choose from for sampling, and we still have four more weeks here!.  Besides this, many of the sites appear quite old, still contain preserved bits of bone and eggshell, and hopefully will have lots of diet remains in them as well.  I'm excited about the findings and already am thinking about an additional study in this area in the future.

Thanks for all your questions and I'll look forward to hearing from you again next week!

Steve Emslie