Snow blanketed the ground when we awoke on Boxing Day, though it had largely melted before we left camp about 2:30 pm, to start the walk east to Cap Noir. Our task for the day (and the next) was to count Antarctic fur seal pups, and also any vagrant subantarctic fur seal bulls. Fur seals were all but extirpated from the Kerguelen Islands by skin hunters 300 years ago, and only began breeding again on the main island (at Cap Noir) about 30 years ago. They are now abundant on the north-east coast – we counted over 10,000 pups, and for long stretches of coast there were no gaps between the harems, each defended by a large aggressive bull. This made for challenging counting (and walking) as our heavy back-packs reduced our response times. Many territories were further inland on coastal slopes and the plateau edge, requiring us to negotiate between bulls to see all the pups. It was the peak of the breeding season, with much fighting between males, females giving birth, and males reaping the rewards of their exertions.

We found two male subantarctic fur seals – a species that breeds abundantly on Amsterdam Island to the north. It was close to nightfall when we reached the hut at Cap Noir, having been distracted by a distant herd of reindeer, nesting northern giant petrels, patches of Pringlea, and a white-chinned petrel calling from its burrow. We also stopped for a while at a gentoo penguin colony a kilometre before the hut. They are timid birds, but very inquisitive if you lie still.

Day 2 was a 9-hour walk south along the coast to Cap Ratmanoff. After counting the seal pups at Cap Noir, we followed the cliff top south-east to Cap Digby, stopping to admire a picturesque Kerguelen shag colony, and a large patch of Pringlea (Kerguelen cabbage). This large herb is endemic to three subantarctic island groups in the southern Indian Ocean, and is highly vulnerable to browsing by rabbits (and probably reindeer). It is suspected that these isolated patches on Grand Terre have developed chemical resistance to browsing.

We started to encounter huge flocks of moulting king penguins on the plateau above Cap Digby, and their numbers continued to increase as we walked the narrow 6 km-long isthmus separating Lac Marville from the sea. As we descended to near sea level we also found more and more moulting juvenile elephant seals, often piled in heaps in mud holes, many of which become death traps. After crossing the outlet to Lac Marville we stopped for lunch and to catch dinner. We played and lost two large trout that broke the 9 kg line, but Charly landed three pan-sized fish that we later marinated for dinner.

The east coast of Grand Terre for about 20 km south from Cap Digby holds perhaps the greatest biomass of any coastline on earth, with thousands of elephant seals and tens of thousands of king penguins per kilometre, centred on the 90,000 pairs of king penguins that breed at Cap Ratmanoff. It was evening when we reached the colony, and we headed straight to the inland hut (1.5 km up the river), as the hut at the colony was occupied by a research team.

The third and last day would be the longest, and we left the hut at 6:15 am, to allow time at the enormous king penguin colony before starting the final long march to Port aux Français. The next four hours south along the coast was easy walking on firm black sand to start with, then on Leptinella plumosa sward between the elephant seal wallows. We occasionally cut across the base of headlands, on drier Acaena magellanica sward, spotted with ponds. While attempting to photograph a flight of Eaton’s pintails, I was distracted by a pair of southern skuas that had caught a young rabbit, and proved to be far more efficient at skinning it than I had been 5 days earlier. I don’t know why they bothered, as they swallowed the skin anyway.

We had been blessed with fine weather for most of the walk, but the westerly wind picked up as we turned west across the Morne Desert and along the northern shoreline of Baie Norvegienne. Soon after leaving the east coast (at 2:30 pm) we could see the CNES satellite tracking radar ball 14 km away – our road-end destination only 3 km from Port aux Français. But that is as the skua flies, and we had many embayments, river mouths, lakes and marshes to walk around, and it took nearly 5 hours to cover the distance as the headwind strengthened. We received an adrenaline boost an hour before the end while searching for Kerguelen tern nests in the tundra-like vegetation. We found two nests each with a single egg, but soon got a greater surprise. The calling terns attracted a vagrant long-tailed skua – possibly a new bird for Kerguelen, and a lifer for me. They specialise in harassing Arctic terns nesting in the Arctic tundra, trying to get them to drop their prey. It was fascinating to watch the Kerguelen terns respond to a distant genetic memory of an ancient enemy, and to snap some quick record shots against the ever-present back drop of the CNES radar ball, which never seemed to get any larger no matter how many hours we trudged towards it.

Te Papa curator of vertebrates Dr Colin Miskelly’s participation in seabird research programmes on the French subantarctic island groups of Crozet and Kerguelen was at the invitation of Dr Charly Bost of the CEBC laboratory (Chizé) of CNRS (Centre National de la Recherché Scientifique), France, and was supported by the Institut Polar Français Paul Emile Victor (IPEV) and Te Papa.

Previous blogs in this series

Reunion Island to Crozet Islands

Two days on Ile de la Possession, Crozet Islands

Arrival at Iles Kerguelen

Port aux Français

Cap Cotter and the macaroni penguins

Christmas among macaroni penguins

Subsequent blogs in this series

A week on Ile Mayes, Iles Kerguelen

The petrels of Ile Mayes, Iles Kerguelen

A week on Ile aux Cochons, Iles Kerguelen

The petrels of Ile aux Cochons, Iles Kerguelen

Kerguelen freeganism

Deep science