Friday 9 January 2015

Antarctica part 3 - Marine Mammals

Humpback Whales are recovering well from the devastation of the whaling years (from 1904 to 1965). The population that visits the Antarctic Peninsula for six months a year comes south to feed up on the abundant krill. During the southern winter, the whales swim north to warm waters off Brazil and South Africa to breed, where they eat little or nothing. This pair were so busy feeding that they took little notice of our zodiacs. The animal on the right has its head above water: the mouth is clearly visible (and many on the image to enlarge). I find watching Humpbacks even more of a thrill than watching penguins!

The Antarctic Minke Whale is much smaller than the Humpback, and usually much shier, but occasionally an inquisitive individual will cause a surprise by nosing up to a zodiac. They also migrate to warmer waters to breed. The Japanese still take over 400 Minkes from Antarctic waters annually for 'scientific' purposes. An interesting theory that I recently heard suggests that if Greenpeace and the IWC (International Whaling Commission) were to stop condemning Japan, then Japan would be likely to announce that their 'scientific' programme is complete and to back off of their own accord.  

We had various encounters with Orcas or Killer Whales during the two months I spent on board this season. My niece Sarah took this photo when a pod spent time close to the ship. A closer look between the fins of the adults reveals the head of a young calf! Different groups of Orcas have specialized diets: we believe that this is one of the resident Gerlache Strait pods that feeds on seals. Sometimes they ram icebergs with all their weight to try to dislodge sleeping seals. Another population specializes in hunting penguins; while a third targets Minke Whales, tiring them out by preventing them from surfacing to breathe. 

On the beaches of South Georgia, the main battles of the Elephant Seal beachmasters takes place in October. I took this photo in November, when the largest 12-year-olds were already back at sea after their exhausting month of defending harems, fighting and mating. Nevertheless, these young males were huge and fearsome beasts, and a few were still finding females to mate with. Here the beach was so crowded with seals that the King Penguins had to weave their way between them to reach their colony. 

These Elephant Seal pups were about ten weeks old when we spent an hour with them as we stood in the shallows, helping passengers onto zodiacs. They were constantly on the move, nuzzling each other, the zodiacs, and our boots. Their mothers wean them at three weeks, but they don't know that! So here they stay, each one patiently waiting for her return, until hunger finally forces them to swim out to sea and learn how to dive and catch fish and squid. An adult's average dive is for 20 minutes, to a depth of about 500 m. Males reach a weight of 3.7 metric tons. 

The Leopard Seal is a predator that all our passengers hope to see. Armed with a mouthful of razor-sharp teeth, they specialize in catching penguins in the water, but their diet includes squid, krill, fish and young Crabeater Seals too. The combination of long neck and large head makes even a distant Leopard easy to identify on an ice floe - if it's facing sideways!

Weddell Seals are best identified by mottled pelage, large rotund body and small head. While most Antarctic mammals and birds depend on krill for their food, Weddells feed mainly on fish, diving to great depths and often feeding under ice. At Deception Island in November we came across a Weddell Seal feeding an albino pup: pure white, with pink flippers. Unfortunately it is likely to have a short life at sea, as it certain to be conspicuous to predators. It may also have problems with weak eyesight.  

Finally, the region's most abundant mammal: the Crabeater Seal. We often see these seals hauled out on ice-floes, usually looking slender, elongated, and plain buff in colour. Misnamed by early sealers, Crabbies feed only on krill. They feed mostly at night, when they are vulnerable to attacks by Orcas and Leopard Seals. Making estimates of their population has proved difficult: totals from 10 to 75 million have been proposed. My usual thanks go to those who have provided photos to share. 

Thursday 8 January 2015

Antarctica - part 2

My last blog was all penguins. Now for three albatrosses. What a contrast - the non-fliers and the constant-fliers! This adult Southern Royal Albatross is taking a break from nesting this year, since it's half a world away from its nesting grounds on Campbell Island, off New Zealand. My staff colleague Bruce took this portrait in the Drake Passage, south of Tierra del Fuego. These great albatrosses (with wingspan of up to 3.5 m) are such masters of air currents that they hardly need to flap their wings, and spend the non-breeding years constantly circumnavigating the globe at latitudes of about 50 degrees South. Their breeding population is estimated at 8,500 pairs.  

The Wandering Albatross is a very close relative of the Royal. Here we see a fully grown juvenile begging for food from a parent - on its nest on Prion Island, off South Georgia. It takes a pair of Wanderers a whole year to complete a nesting cycle - three months of egg and nine months of chick in nest. So when half-grown this chick will have endured a harsh winter of snowfalls and gales. Once it fledges, it must learn to fly and catch squid by itself - its parents have finished their work, and now take a year off to roam the southern ocean.

 Also in the same family, but far smaller and darker, is the elegant Light-mantled Sooty Albatross, another emblem of the South Georgia region. Breeding sites echo to the sound of their mournful cries, as pairs pass alongside the cliffs in synchronized flight. The large head, white eye-ring, and pointed tail are characteristic. Unlike their larger relatives, sooties can raise a chick each year. 

Petrels are close relatives of albatrosses; and there's not much size difference between a sooty albatross and this Southern Giant Petrel. This is one of the white morph that occurs in small numbers among the more common grey-coloured giant petrels. Here seen on nesting grounds in the South Shetlands, giant petrels nest in loose colonies and are easily disturbed while breeding. I took this photo with my Nikon Coolpix through the telescope. 

Cape Petrels are often firm favourites with passengers in the Drake Passage, as they follow ships in friendly gangs, riding the air currents for hours and often passing conveniently at deck height. They are also known as Pintado, the Spanish name for 'painted,' since the white back seems to be splashed with black paint. The scientific name Daption is an anagram of Pintado, and has no latin root. 

Finally, we were happy to see that Antarctic Shags had hatched their chicks well before Christmas. These beautiful cormorants nest in small colonies, and can raise three chicks in a good year. The nests are used each summer for decades, perhaps centuries, and comprise fresh seaweed bound with guano. While krill is the preferred food of most Antarctic birds, shags supplement this with small fish. Many thanks to One Ocean staff and passengers for the use of their images. Next time, some Antarctic mammals.....  

Wednesday 7 January 2015

Penguins! The Essence of Antarctica!

I am recently back from two months on board ship with One Ocean Expeditions, with four groups of passengers. All four voyages visited the Antarctic Peninsula; the first two also visited Falklands and South Georgia. One of the most special experiences is the King Penguin colony at Salisbury Plain, South Georgia, which has an estimated 60,000 breeding pairs. Here most of the downy chicks (9 months old) are cooling off by flattening themselves on the cold ground, since they soon feel the heat when the sun shines. (Click on the image to enlarge.) 

The Rockhopper Penguins on Westpoint Island in the Falklands choose to nest among Black-browed Albatrosses. When a predator flies over, such as skua, caracara or Turkey Vulture, the long-necked albatrosses help to keep it at a distance. In November the albatrosses were incubating a single egg, while the Rockhoppers had two.

Macaroni Penguins are the world's most abundant penguin, but it's easy to miss them in South Georgia as most of their colonies are on the inaccessible southern side. On our first voyage, we were lucky enough to watch them from zodiacs at a small colony on the east side of Elephant Island, though it was hard to keep bins and cameras steady in the swell. Macaronis lay two eggs, though it is rare for the first one to hatch. 

Down on the Antarctic Peninsula, we had a great day for visiting the Adelie Penguins. This group were heading away from their nests, towards a stretch of shore clear of icebergs. As with all penguins, males and females share the nesting duties and regularly take turns with incubating and feeding young. The decline of Adelies on the Antarctic Peninsula is linked to a reduction in winter sea-ice. Krill, their staple food, feeds on algae under the sea-ice. In the Ross Sea, the vast Adelie colonies are stable as they are much further south, where the ice levels remain unchanged.  

This Chinstrap Penguin is busy bringing another stone to the nest, essential for keeping the nest-base well drained. Eggs laid on snow, ice or mud fail to hatch. In a good year, both eggs hatch and two chicks may fledge. Hatching occurs around Christmas, with the youngsters taking their first dip two months later. At this time Leopard Seals are likely to be patrolling the shallows, looking out for first-time swimmers. 

Finally, a photo from Christmas Eve. This Gentoo Penguin had just hatched both chicks on a good stone-based nest. The chicks will be fed at regular intervals by regurgitation. In February they are nearly fully grown, very mobile and inquisitive, frequently walking up to visitors and pecking at rubber boots, cameras and gloves. In my next post, I will feature some of the region's flying birds.