Saturday, February 14, 2009
Penguin Week - Chinstrap Penguin
Deception Island was the scene of this years best Chinstrap Penguin (Pygoscelis antarctica) encounters so I am going to concentrate on my one visit to Baily Head, a large Chinstrap colony on the east side of Deception Island. The photo above shows a small portion of the birds waiting on the black volcanic sand beach at the landing site. Below is an image of Deception Island and a marker showing where Baily Head is located.
I have zoomed in on Baily Head below and have added a red line to show the typical route most people take when they visit this site. I will reference this view to help explain where many of the images were taken.
Below is an shot from the Oceanites Image Library. This photo was taken by Ron Naveen, probably about 10 to 15 years ago. Note the large pink areas on the slope in the center of the photo where the Chinstrap colony covers the entire top third of the rim. This photo was taken from a helicopter above the west side of Baily Head looking east (left of the red line in the photo above looking to the right. The end of the red line is at the edge of the rim in the top center portion of the photo and the beginning of the red line is located off the photo to the left).
Below is a photo I took in December looking in the same direction except I was on the ground, somewhere about dead center in the photo above. You can see the same dark S shaped curve to the rim in both photos.
The photo below is from beyond the top of the S shaped rim looking west this time. Notice that there are no penguins nesting in the center of the slope in this photo compared to the same area in Ron's photo above. The people in both photos helps give a frame of reference to the locations the photos were taken. The red line from the Google Earth image would end right about where the people are in this photo and begin off the photo to the right.
The photo below is another photo from Ron Naveen at Oceanites. This one is again taken from a helicopter just south of the rim looking back at the landing beach. The dark cliff in the foreground is the edge of the S shaped rim I mentioned above. The beginning of the red line in the Google Earth image is on the beach in the center of the photo below.
The landing at Baily Head is one of the toughest in the peninsula because of a persistent, usually large, swell. The day we visited was one of the tamest landings I have done, much to the relief of the staff who have to maneuver the zodiacs and passengers on and off the beach, sometimes a nearly deadly chore. After landing we made our way through a narrow melt stream gap between the glacier and the rock cliff where many of the chinstraps also commute back and forth from sea to nest.
The amphitheater of breeding Chistraps is overwhelming. Every time I visit it is still gives me a chill to walk around the corner and enter the stadium filled with screaming penguins.
Most people make their way to the edge of the bowl and look over the edge then turn around to take in the scene from another perspective. On this trip Aileen and I were the first to venture into the bowl and we headed to a different part of the rim than most of the others to take documentary photos and count nests at some of the smaller colonies where we can effectively count.
Once people come down from the sheer size and configuration of the place, they realize that all around them are individual penguins going about their lives and they start to notice what is happening in the colony at a smaller scale.
Some birds are sitting on nest with eggs. Notice the bare patch of skin located just above the egg in this photo. This is a brood patch, a place on the belly where the feathers have fallen out to enhance heat transfer from the brooding adult to the eggs it is incubating. I am always amazed that the penguins call pull this area closed so tight when they return to the sea that the cold seawater does not come in contact with the bare area.
Others have progressed far enough along in the breeding cycle that the eggs are beginning to hatch. We visited Baily Head just as the chicks were hatching and we saw a number of nests with chicks and eggs. The nest below had a chick that had probably hatched the day before and one egg that was hours or minutes away from releasing another new chick.
Other nests had their full complement of two chicks already hatched.
One of the impressive things about visiting a place like Baily Head is the opportunity to see the complete drama of life. Skuas were a constant presence, grabbing eggs and small chicks whenever the opportunity arose. There were also the remains of recently dead adult penguins that had died from unknown causes, perhaps the result of an escape from a leopard seal but with deadly wounds, or some other catastrophic injury. These are great teaching tools to show the amazing skeletal structures of these sturdy birds and their adaptations for flying in a denser medium than air.
The photo below shows the remains of a flipper. Once covered with a layer of skin and very small, very dense feather, the bones show the fusion of an appendage that once propelled an ancestral bird through the air.
As I suggested above, the number of breeding Chinstrap Penguins at Baily Head has noticeably declined over the last 20 years. How much is uncertain because of the difficulty of getting accurate counts of such a large colony, however examination of reference photos like the examples above can help us at least see how much area is now free of the clamour of breeding Chinstraps.