Notes from the Field: Seabird Research Reveals Impact of Ice Decline in Antarctica

Where to begin!? I recently returned from a six-week expedition to Antarctica, living and working at the U.S. Palmer Research Station to study the populations of penguins and other seabirds. I’m still in awe of the whole experience.

Palmer Station is the base for a long-term ecological research program, where scientists are studying all aspects of the Antarctic ecosystem. The fieldwork conducted there through the Polar Oceans Research Group has been ongoing for 40 years, resulting in the collection of a lot of data. While scientists have determined that the climate is severely warming and affecting all regions in the world, the greatest effects are seen in Antarctica. Declining sea ice levels are negatively impacting many species of wildlife that depend on it.

Sea ice is crucial to the Antarctic ecosystem, and its loss can have profound effects. One example of this can be found by examining a small crustacean called krill. This animal feeds on the algae that grows underneath the ice and is a primary staple in the diets of many species, including penguins. Declining sea ice means fewer krill, which means less food for the fish that eat them and as a result, a depleted food supply for penguins and the rest of the food chain.

Sea ice losses can occur from both warmer air above it and warmer water below, and increased air and water temperatures means more snow. This makes it difficult for penguins to build their nests and when the snow melts, the nests are at risk of flooding and these birds may find their eggs floating in puddles.

Upon my arrival at Palmer Station, we began conducting a breeding chronology study with two colonies of Adélie penguins on two local islands. We selected a few nests to observe throughout the season – our observations included periods of birds laying their eggs, the chicks hatching, and the chicks heading off on their own. These nests were monitored daily for predation and for the exact dates of chicks hatching. We also chose nests to be assessed for body condition and egg morphometric data. We took measurements and weights of birds and eggs to obtain a sampling data size of a larger population.

As part of another aspect of the program, we counted the number of individual birds in colonies of Adélie, gentoo and chinstrap penguins. One island was home to 6,000 gentoo penguins! Boy, did my thumb hurt that day from using a clicker counter. Unfortunately, most Adélie colonies were in decline from recent years’ data while gentoo numbers were increasing. One of the reasons for this is Adélie penguins rely more on sea ice than gentoos for feeding.

The sea bird program not only involves the study of penguins, but also every other species of bird surrounding Palmer Station, including giant petrels, brown and south polar skuas and kelp gulls. These species were monitored in various ways including mark-recapture, leg band re-sights and nest observation. We even deployed satellite transmitters on southern giant petrels – the data from the first transmitter we analyzed showed that the bird had traveled 1,500 miles in just 10 days!

In addition to bird surveying, we were asked to conduct a marine mammal census by identifying species, behaviors and group size. As a seal keeper, seeing various seal species in the wild was just beyond anything I could have imagined – Antarctica is home to crabeater seals, weddell seals, ross seals, elephant seals, fur seals and the infamous – and dangerous – leopard seals.

The Detroit Zoological Society has worked with the Polar Oceans Research Group for a number of years – its founder, the world-renowned polar ecologist and penguin expert Dr. Bill Fraser, was a consultant on the design of the Polk Penguin Conservation Center. This is the second time a member of our animal care team has been invited to take part in this rare and extraordinary opportunity to conduct scientific research in Antarctica during the austral summer.

– Flo Yates is a zookeeper for the Detroit Zoological Society.

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