March 3, 2013
We’ve just completed another successful week of the cruise, filled with continuing surveys of marine birds and mammals. But the highlight was deploying our first satellite tag on an emperor penguin!
The day (Feb. 25) started with a 5 a.m. wake up call from Jerry Kooyman, who had spotted some emperor penguins during his watch. Three penguins were scattered within two kilometers of the ship on some large flat ice floes. There was lots of thin ice between the floes, but it looked soft and we were pretty sure we could navigate the zodiac to one with a penguin, about 300 meters from the ship. After donning our cold weather gear and grabbing our backpacks with field equipment (supplies we’d need to weigh the penguin and attach the data logger), we climbed into the zodiac and were on our way.
Once in the zodiac, we headed toward the penguin, but it was slow going through the ice. Although the bird seemed close, it took us almost an hour to navigate the 300 meters to the floe. Periodically we had to stop and push ice away from under the zodiac or change our direction, looking for more open water. When we reached the floe, we jumped out of the zodiac and started our slow appoarch toward the penguin. Unfortunately, it dove into the water before we were able to capture it. Disappointed, we returned to the zodiac to come up with another plan.
When we radioed back to the ship for an update, we were happy to hear that another penguin was on a floe about 1.5 km away. The ice conditions would have caused us a very long trip in the zodiac, so the RV Palmer lead the way, breaking the ice for us to within 100 meters of the floe. We left the path made by the ship and started working our way toward the second penguin.
When we arrived at the floe, we hopped out of the zodiac and slowly approached the penguin, this time resulting in a successful capture! We quickly weighed the bird (21 kg) and attached the satelitte tag to the feathers on its back. The tag is attached with a special glue that lasts in seawater for weeks or months. Thirty minutes later, we released the penguin with a satellite tag that will provide us its location over the next 10-11 months.
This will be one of scientists’ first tracks of an emperor penguin during its post-molt foraging period. Successful foraging during this time of the year is likely critical to the reproductive success of emperor penguins because the birds need to gain a significant amount of weight (specifically fat) to survive the long fasts during the breeding season (females fast for approximately 60 days, while males may go without feeding for close to 110 days).
During the last week, the bird (which is now known as EP1) has traveled 150 km southwest from where it was tagged. Recently it’s been spending time near the Nordenskjöld Ice Tongue (-76.250, 163.000; ~230 kilometers north of McMurdo Station). We are excited to see where the penguin travels over the next few weeks before Antarctica’s autumn breeding season.
We’ve continued our search for emperor penguins, but have only seen a few. This is not unexpected , as we are spending most of our time in open water focusing on concurrent oceanographic studies aboard the RV Palmer. Yesterday, another emperor penguin was spotted in the early morning, but unfortunately it decided to go for a swim while we were preparing to launch a capture team.
Fingers crossed that we have the opportunity to instrument a few more birds before heading to the eastern Ross Sea where we plan to deploy the bulk of our data loggers.