This week at Macquarie Island: 27 January 2017
An albatross and skua update, Murray shares his tour-guiding experiences, Stay Here goes boating, and congrats to Pete Raymond who welcomed twin boys to the family.
It’s an exciting time of year for the albatross team on Macquarie Island as the light-mantled, black-browed and grey-headed albatross eggs are hatching and the wandering albatross are returning to breed.
Field biologists Penny Pascoe and Kim Kliska, along with assistance from the wildlife ranger Marcus Salton, have been out and about monitoring the hatching success of these species. The albatross and giant petrel program contributes data to the Agreement on the Conservation of Albatross and Petrels (ACAP) to develop an understanding of the global population trends of these species. Towards the end of December the black-browed albatrosses were the first to be heard and then seen hatching. Grey-headed albatross were next, and by late December/early January, light-mantled albatross chicks have been spotted.
One parent will remain with their chick guarding them from predators while the other forages for food to return to the chick. Once they grow and can defend themselves, both parents begin foraging trips and both feed the chick until they fledge the nest in late March/early April. Seeing cute bundles of fluffiness squished under their parents or sitting tall on their nest 'stacks' has been a highlight of recent fieldwork.
The largest of them all, the wandering albatross, have been returning to court, mate and lay eggs. The chicks from 2016 all fledged by late December, around the same time that male wanderers were spotted returning to the island to begin nest building for their life long partners or to attract a mate. Wandering albatross mate for life and it has been interesting observing known partners returning to the island and new pairs forming. With only five eggs laid last season, and low numbers breeding on Macca, every egg counts towards the survival of the population on Macquarie Island.
The tour-guiding experience
Last week saw the start of the peak season of tourist ship visits, with the Professor Khromov (also known as Spirit of Enderby) and L'Austral calling in. This is keeping the TasPAWS staff and several volunteer guides busy at the station and at Sandy Bay where the colonies of both king and royal penguins are the attractions.
The Professor Khromov (Heritage Expeditions) came first, unusually using Hasselborough Bay for the landing at the station, as we have seen very little of the prevailing north-west wind this month. The station visit consists of a walk around the isthmus to the lookout at the start of Doctors Track, and then to the Mess for tea and scones with a little retail therapy (Macca postcards and tea towels on offer). Those expeditioners lucky enough to be guiding get a lift to Sandy Bay with the ship, which typically involves an overnight stay on the ship.
L'Austral (Ponant Cruises) was delayed earlier in its voyage and visited the station only to pick up three expeditioners, before heading to Sandy Bay. Compared to the Prof K (48 passengers), L'Austral is huge with 200 passengers. It's also a luxury vessel, much like a five star hotel, with beauticians, a spa, a pool, live music in the bar and a theatre with live shows. As we were picked up at 5.45 am, we were offered breakfast on board; the croissants and fresh fruit were spot on. It was a very long day as only 50 passengers at a time were allowed on shore, and the last of us left the beach around 6 pm. Back on board we were treated to a drink in the bar and a whistle-stop tour of the facilities on board from Jacque and Jess, two former Macca expeditioners now working as expedition guides for Ponant. For deprived expeditioners the luxury was quite surreal!
Helping with the tourist guiding reminds one of just how special Macca is – when the guests' jaws drop off and hit the beach. After a while you forget when walking every day past the ele seal fight club and the mobs of penguins just how unique this place is.
Great skua census
This week marked the end of the 2016-17 Great Skua Census. The team at Macca have worked together to search four study sites that cover 28% of the island! It was a huge effort! First we searched for all their nests in November and then revisited their nests in January to see how many chicks were raised.
The skua are well known for being curious observers and cunning predators. Skua steal milk from young elephant seal pups, poach small chicks from beneath distracted gentoo parents and can zoom in and out of a king penguin colony with a whole egg in mouth! These are just some of the food sources skua utilise on the island in order to produce their own eggs and chicks.
The search for skua nests gave us a different perspective into the lives of the skua. In spring, skua were forming partner bonds and establishing a breeding territory. The pair vigorously defended their breeding territory from intruders – other skua and humans! By November, most pairs have established a nest and are incubating one or two eggs. They are often well hidden when they’re on the nest, with just their head and tail visible across the landscape. Their eggs hatched from late November and by January chicks were starting to get quite large. While the chicks are quite mobile within hours of hatching, the parents must bring food to them. Some territories become littered with penguin eggs, bones and seal fur: a good sign the chicks have been well fed.
It has been great to get to know another side to these fascinating birds.
The census is part of a long-term monitoring program run by the Tasmanian Parks and Wildlife Service that assesses the Macquarie Island skua population status and trends over time. The data collected this season will be incorporated into the database and analysed over the coming months. The analysis will include processing of skua poo samples, which give us insights into the diet of skua adults and their chicks.
With the tourist season in full swing we are experiencing many visitors and new arrivals, with some of the summer team arriving via cruise ships.
Friday 13 January saw some different types of arrivals at Macca. Firstly we were greeted with sunshine that lasted all day. This was followed up by the arrival of a chinstrap penguin, who seated itself on top of a pile of sand to get a bird’s eye view of the new pipe work being laid across the Isthmus (for those who read station news last week or follow ABC online this is old news).
Last but not least was Pete's announcement that his daughter had given birth to twin boys the night before, and so a few toasts were raised around the BBQ. The next night Rocket baked twin apple cakes welcoming Lincin and Jaxon to the world (unfortunately there is no spell or grammar check with cake writing and the BSS got it wrong).
Our congratulations go to Pete and his family.
Stay Here on tour
A suitable weather window last Saturday afforded the team an opportunity for an afternoon run in the IRB's to Green Gorge, to move some provisions and equipment down the island.
One of our newest team members, Stay Here, was keen to join the trip, see some more of the island and meet some locals.
If we flashback between 30 million and 11 million years ago, we get to a time when Macquarie Island didn’t exist yet and was believed to be only a spreading ridge on the floor of the southern ocean. Fast forward to somewhere around just over half a million years ago and you get to when the Macquarie Ridge first appeared above sea level to make itself available as a resting and breeding place for wildlife. In 1997, when the island was listed as a World Heritage site, it was listed for its geological significance not its abundant wildlife as one would first imagine. Sure, rocks aren’t as cute to photograph as penguins, but some pretty amazing things went on here, and there are many different forces that have literally shaped the island we know today.
Macquarie Island is totally oceanic in form, all rock units having formed on or beneath the ocean floor. On the ocean floor, lava flowed out of fissures running for thousands of kilometres across the seabed creating ridges, and these ridges are visible above sea level in only a few places in the world, such as Iceland and Macquarie Island. About 10 million years ago, this ridge stopped spreading: instead of moving apart, areas on either side of the ridge started to squeeze together forcing the oceanic crust and parts of the upper mantle, upwards. Because of this major reversal in geological processes, Macquarie Island started its 2.5 km rise to emerge above the sea surface about 600 to 700 thousand years ago.
Rock outcrops on the northern part of the island have been forced up from about six kilometres below the ocean floor, a unique exposure of rocks from the earth’s oceanic crust. No drill hole has ever penetrated to these depths and so these exposures provide a rare opportunity for geologists to gain an understanding of geological processes from some of the deepest rocks in the earth. Elsewhere, our knowledge is confined to the upper few kilometres of the earth’s geology, leaving the 3000 km to the centre of the earth in the realm of the unknown. It is very rare to have rock outcrops of this type above sea level in an oceanic setting and there are no other known locations in the world which have such well exposed rocks from the oceanic crust.
Equally impressive is the island’s ongoing rapid rise out of the sea, making it one of the most active geological regions in Australia. Recent estimates suggest that since about 6,000 years ago the island continues to rise at an average rate of about 0.8mm per year. Numerous old beaches, or areas eroded by waves, occurring at altitudes ranging from six metres to 400 metres indicate that the island has continued to rise above sea level during this time.
All the knowledgeable bits for this article are taken from the TasPAWS booklet: ‘A new arrival: the geological development of a young island’ by Michael Pemberton, Garry Davidson and Jennifer Burton.