Isla Terhalten, ChileThis morning we left our sheltered cove on
Isla Lennox to once again head out into the open waters and
Isla Terhalten. Today the seas are much calmer and I hope to have another shot at getting on to the island. As we approached the island you could see shiny white dots that were actually the bellies of rockhopper penguins filing down the rocky cliffs, headed out to sea to forage for fish. As the boat got closer some of the penguins farther up on the rocks stopped abruptly and stared out at the boat, while others turned and scrambled back up into the grasses on the edge of the cliff. The small group that had already made it down to the water porpoised through the waves off the starboard side of the
Chonos and out to sea.
Before I knew it I was wearing a life jacket and sitting in the small zodiac headed straight for the rocky cliffs of the island. When the tiny inflatable boat ran up near a low rock face Manuel effortlessly jumped onto the island and made it look easy. Now it was my turn. I climbed to the front of the zodiac, over the rope webbing protecting the boat from the sharp rocks and barnacles, and tried to scramble up onto the island. Let’s just say I was not as graceful.
My feet and hands could not get a hold on the very slippery, algae and barnacle covered rocks but luckily Manuel was able to grab my life jacket and help me to shore. Once standing upright I took off my life jacket and passed it back to the zodiac, noticing over my right shoulder that an enormous male southern sea lion was watching us from the rocks about 20 feet away. Before I could get my camera out of my pocket he slipped into the water to investigate the second launch arriving to his island. His massive head bobbed in the waves about 10 feet from the zodiac. Two female sea lions went in after him and poked their much smaller heads out of the water on either side of his.
He watched the zodiac intently as the rest of the team made their way onto the island and then lost interest and disappeared under the waves as the small zodiac headed back to the
Chonos. Now that the entire team was finally on Isla Terhalten, we made the climb up into the largest of the three colonies located on the island. At the top of the cliff where the steep rocks ended and the tussock grass began, were the small group of rockhoppers that had stopped in their tracks when they first saw our boat.
They watched us closely, unsure of what to make of us. Southern rockhopper penguins in Chile breed in such remote and harsh locations such as Isla Terhalten that most have never encountered humans. Once at the base if the colony, our first matter of business is to measure out areas called plots, in order to get accurate counts of nests and eggs. Four ropes tied together to make a large rectangle designate the area in which to count, although attaching the ropes to small trees or dense clumps of tussock grass around the colony is much easier said then done.
This colony is situated on either side of a small, muddy creek bed. The mud is so thick in some areas that if you stand still for too long your boots are sucked in to the mud past your ankles. The colony is also on a hillside and climbing up the slippery rocks and fallen trees can be a recipe for a face full of mud and guano. Most importantly, you have to be very careful about where you step as to not disturb any nests or eggs. The penguins, not sure if we meant them harm, abandoned their nests and ran into the surrounding tussock grass as we entered the colony.
Luckily, the striated caracaras watching from the nearby bushes were also too afraid of us to come into the colony and steal the now unguarded eggs.
Once the ropes were in place we moved quickly through the colony counting nests and eggs and after a few minutes the rockhoppers cautiously returned to their nests. By counting the number of nests with eggs in them we can get a much more accurate idea of the total number of birds in each plot. Incubating eggs requires both parents as they have to be able to switch of between sitting on the eggs and foraging for fish. Pairs that lose their mate during the breeding season will eventually be forced to abandon their eggs to hunt for fish. Unguarded eggs are quickly taken by predatory birds, such as caracaras, that also live on these islands.
By counting nests we can assume that any nest with eggs must have two penguins. Our first plot had 141 successful nests, which means that there are probably close to 282 southern rockhopper penguins just in that 20m X 10m area. As we continued up through the colony we did 3 more plots, each with at least 100 successful nests. Around 85 percent of the nests that we counted had two eggs in them and I only saw a handful of abandoned nest sites in the 4 plot areas.
It seems that the remote location and dense vegetation of Isla Terhalten is helping to protect these penguins from pressures such as habitat encroachment and introduced predators. Unfortunately even the harshest of locations cannot protect them from the larger problems of over fishing and climate change that are pushing many species of penguins to the brink of extinction. Leaving the colony, we radioed to the
Chonos to establish a new pick up location and made our way back down to the cliffs. Along the way we passed a pair of Magellanic penguins in their burrow, and an ashy headed goose guarding his nest site from on looking striated caracaras.
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