This week at Macquarie Island: 3 February 2017

This week we catch up on white-headed petrels, expeditioners and the Australia Day swim, our unexpected beach visitor and Stay Here off on tour.

White-headed petrel monitoring

White–headed petrels are a threatened seabird that breed in burrows on Macquarie Island. They are one of the larger burrowing species (between 580 – 810 grams) and the most abundant and widely distributed of the petrels breeding on Macca.

Their global population is in decline due to interactions with invasive species (such as cats and rabbits) and the population on Macquarie Island is listed as vulnerable under the Tasmanian Threatened Species Act 1995. For these reasons, white–headed petrels were selected as a key species to monitor pre–and post–MIPEP (Macquarie Island Pest Eradication Program).

Over the past two weeks, Field Biologist Kim and myself have searched two of the long–term white–headed petrel sites. Our aim was to identify the number of breeding attempts within the site and reproduce photos of vegetation, which can be used to relate changes in their population to habitat. We found many white–headed petrels breeding in both sites – some with small chicks! In a couple of months these sites will be checked again to see how many of the breeding attempts produce full–grown chicks (i.e. were successful breeders). We even found some other burrowing species co-habitating the site – sooty shearwaters!

It was great to see the white–headed petrels have survived the cats and rabbits that were present on Macquarie Island. Their breeding sites are looking in pretty good condition this year, so hopefully they will have a good breeding season. The data collected this season will be incorporated into the long–term database and analysed in the coming months to assess their population status and trends. Fingers crossed for some more good news about the wildlife living and breeding here on Macquarie Island.

Marcus Salton

White-headed petrel habitat looking good post Macquarie Island pest eradication program
White-headed petrel habitat looking good post MIPEP.
(Photo: Marcus Salton)
A white-headed petrel sitting in a burrow
White-headed petrel prospecting.
(Photo: Marcus Salton)
A white-headed petrel chick sitting in its burrow- photo taken in March 2010
White-headed petrel chick - photo taken in March 2010.
(Photo: TasPWS)
A picture of a white-headed petrel sitting on its nest.
White-headed petrel close up on nest.
(Photo: Marcus Salton)
A picture of a sooty shearwater on a nest in a white-headed petrel site
Sooty shearwater on a nest in a white-headed petrel site.
(Photo: Marcus Salton)

Australia Day at Macquarie

Weather can make or break an event here on the island: on Australia Day we were lucky enough to get a sunshiny break just as it was time for the traditional two beaches swim.

Swimmers met in the middle of the isthmus for a photo opportunity and then followed the Australian flags from Buckles Bay on the east across to West Beach for a quick dip on both sides of the isthmus. As ever, wildlife spotters and a lifeguard were on hand. Atmospheric scientist Murray was able to launch one of his UAV's (unmanned aerial vehicles) and got some great aerial shots of the action.

Afterwards a hot spa was called for and was happily filled to capacity, followed by a big cooked brunch and a viewing of the Governor–General's speech. A lazy afternoon with some cricket and a spit BBQ followed, which finished another pleasant day off on the island.

A group of people on the beach ready to go swimming
The 2017 summer swimmers.
(Photo: E. Rodewald)
A man in a penguin suit with a dog statue on the beach
Safety first! Stay Here helping wildlife spotter Chris Howard.
(Photo: Natalie Tapson)
People exiting the surf back onto the beach after the swim.
A quick dip on the east side of the isthmus.
(Photo: E. Rodewald)
People getting out of the surf and back onto the beach.  One man carrying a pretend guide dog called Stay Here
Even Stay Here went for a quick dip.
(Photo: E. Rodewald)
An aerial shot from east to west of the isthmus, showing the sea and beach
Aerial shot from east to west of the isthmus.
(Photo: Murray Hamilton)
An aerial shot of our swimmers in the water.
Aerial shot of our swimmers in the water.
(Photo: Murray Hamilton)
People running across the isthmus
A quick run across the isthmus to West beach with Stay Here
(Photo: E. Rodewald)
people running through kelp on a beach
Lots of kelp to get through.
(Photo: Natalie Tapson)
People running into the water
And then a plunge on West beach - lifesaver on patrol -…
(Photo: E. Rodewald)
A very crowded spa bath with all of the expeditioners that had gone into the sea for a swim
Of course, there was a hot spa afterwards!
(Photo: E. Rodewald)
A cricket game in Market Square
And the traditional game of cricket later in the afternoon.
(Photo: E. Rodewald)

Sperm whale washes ashore

This week we have had an unusual arrival to station: a large male sperm whale carcass. We have become used to seeing animal carcasses on Macquarie Island, with large male elephant seal fights ending the life of some individuals and giant petrels and skua predating on penguins and other seabirds. But this is the first whale we have seen!

These are majestic creatures that we rarely get to see and it is certainly sad to see one in this state. We have all been in awe of the animal’s sheer size: approximately 14.5 metres long according to photos taken with Murray’s drone and probably weighing around 40 tons.

It has also been fascinating to see the island’s resident scavengers make use of the novel food source. The whale skin appears to be quite tough, leaving the giant petrels, skua and kelp gulls to feed on the skin, fat and other tissues as they float ashore. And with the predators focused on this novel food source, the local prey (i.e. penguins and other seabirds) might get some reprieve! It should also get those predators well stocked with energy stores for their winter migrations.

Initially the whale carcass was in the surf zone, but in the last couple of days it was washed ashore and we have been able to collect some precious samples to help us understand more about these amazing animals. So far it has been possible to collect a skin biopsy, teeth, and a blubber sample. The skin and the teeth samples will be very useful for genetic analysis and ageing, respectively, and the blubber can be analysed for pollutants.

Unlike some of the other carcasses on the island, the whale carcass is probably going to be with us for a while. It is times like these we are grateful for the intense winds and cold temperatures so typical of Macquarie Island – without them the smell would certainly linger a lot more! That said, on days of low winds the smell has certainly penetrated station – guess that is life on a nature reserve for you!

Marcus Salton

Aerial shot of a dead sperm whale - using this Murray was able to calculate that the whale was approx 14.5m long
Aerial shot of the whale when he first arrived - using this…
(Photo: Murray Hamilton)
A dead sperm whale in the shallow water before he completely beached himself
Sperm whale before he completely beached himself.
(Photo: Kimberley Kliska)
A dead sperm whale on the beach
And now the swell has pushed him up on the beach.
(Photo: Helen Cooley)
A dead sperm whale lies on its side - lower jaw has been broken, presumably on the rocks
A sperm whale lies on its side - lower jaw has been…
(Photo: Helen Cooley)
Northern giant petrels feed on the dead sperm whale
As is the way of the world, the whale is now a…
(Photo: Kimberley Kliska)
Close up the broken jaw of the sperm whale showing how the teeth sit
Close up of the broken jaw showing how the teeth sit.
(Photo: Helen Cooley)
Two whale teeth washed up on the beach, the teeth are next to a foot showing that the teeth are very large
Two whale teeth washed up on the beach, next to a foot…
(Photo: Marcus Salton)
This shot of the dead sperm whales upper jaw showing how all the teeth fit in there.
This shot of the upper jaw shows how all the teeth fit…
(Photo: Helen Cooley)

Stay Here goes there

This weekend Macquarie Islanders are conducting the first (that we know of anyway) 24 hour island relay to 'walk' Stay Here to Hurd Point and back, a distance of approximately 75 kilometres.

As part of an inter–station ten kilometre challenge, we thought we'd up the ante for ourselves (as most of us are used to a long walk), and try and raise some money for Guide Dogs Tasmania at the same time.

A model of a guide dog sitting out on the porch.
Stay waits patiently on the mess porch for her walk.
(Photo: E. Rodewald)

Flashback

‘Popping’ out of the ocean floor isn’t all that makes our island look like it does. Living in the southern ocean in the middle of the "furious fifties" means the elements have a constant effect on the shape of the landscape. Wave erosion impacts the land as soon as it rises above sea level, with the western side of the island being far more exposed than the east due to prevailing winds being from the north–west. This is evident in the scalloped shape of the coast which has been eroded by wave after pounding wave.

Extensive faulting, which controls earthquake activity, has been another major influence on the continued shaping of the island. There are many large and active faults which have created fault dammed lakes and been responsible for the location of major landforms. Earthquakes can also trigger major landslips, the scars of which cover many of the island’s slopes. It is estimated that an earthquake of magnitude 7.5 on the Richter scale shakes the island every decade. (Our strongest last year was 6.1 in September).

Glaciation was thought by geologists to be the dominant land-forming process up until the mid-1980s, however beach deposits discovered recently over a wide altitudinal range discount extensive glaciation.

Today, other active processes shaping the island are associated with water freezing and thawing: in particular frost heave, which is caused when water percolates into topsoil and expands as it freezes, loosening the soil surface and fine material which can then be removed by strong winds and surface water flow.

Freezing and thawing are also thought to be the major contributors to the terraces, or vegetation stripes which form on the island. On the terrace, the risers (sloping parts) are generally vegetated, while the treads (‘flat’ parts) are gravelled. This process is most active on the riser and the dislodged material falls into the tread. It moves slowly across the tread (which actually slope very slightly) and then down the adjacent riser. Vegetated risers probably indicate that the terraces are not currently active.

And then there is, almost always, the wind: it prunes the plants, removes finer material from bare areas and scours other areas with materials it blows about. Most expeditioners are familiar with the joy of a quick sand exfoliation facial while crossing the isthmus…

All the knowledgeable bits for this article are taken from the TasPWS booklet: ‘A new arrival: the geological development of a young island’ by Michael Pemberton, Garry Davidson and Jennifer Burton.

  The undercut curved face of this large boulder north of David Point bears the hallmark signature of wave action at work. Many thousans of years ago, this rock would have been at the waters edge exposed to the full force of the waves. The gentle lifting of the island over the millennia has now raised this rock to be approx 8 metres above sea level and about 80m from the water. Waves regularly crashing onto the boulder face over time were carrying finer particles of abrasive sand and rock, gradually working away at the exposed face of the rock boulder to create this unique curved surface.
The undercut curved face of this large boulder north of David Point…
(Photo: Chris Howard)
Rock stacks of the 'Labyrinth' on the west coast south of Bauer Bay.
Exiting the rock stacks of the 'Labyrinth' on the west coast south…
(Photo: E. Rodewald)
The rock stacks that are all the remains of a previous coastline - the large one is Eagle Cave on the west coast
The rock stacks that are all the remains of a previous coastline…
(Photo: E. Rodewald)
The landslip near First Gully that took out our water line in the earthquake last year.
The landslip near First Gully that took out our water line in…
(Photo: E. Rodewald)
Fine grained intrusive rock outcrops with spectacular veins of other minerals standout boldly in the landscape on the windswept plateau north of Mt Elder.
Fine grained intrusive rock outcrops with spectacular veins of other minerals standout…
(Photo: E. Rodewald)
The exposed west coast of Southern Macquarie Island bears testimony to the rugged power of nature. Thousands of years of exposure to the elements has carved steep cliffs and promoted the development of extensive gravel scree slopes and boulder dominated coastlines.
The exposed west coast of Southern Macquarie Island bears testimony to the…
(Photo: Chris Howard)
Geometrical patterns observed on the windswept plateau terraces near North Mountain are created by cyclical freeze thaw processes. This process results in a very gradual 'sorting' of the rocks over time.
Geometrical patterns observed on the windswept plateau terraces near North Mountain are…
(Photo: Chris Howard)
Frost heave on the path during a walk last winter, showing evidence of how it moves the soil.
Frost heave on the path during a walk last winter, showing evidence…
(Photo: E. Rodewald)
Linear grooves and smooth polished surfaces observed on an exposed dolerite outcrop on the edge of the plateau east of Bauer Bay demonstrate the erosive potential of wind. Fine sands that have been picked up and carried on the wind have resulted in the surface seen today. The presence of lichen now observes growing on the rock face suggests that this process is no longer active.
Linear grooves and smooth polished surfaces observed on an exposed dolerite outcrop…
(Photo: Chris Howard)
The 'terracing' (layers of gravel & vegetation) caused by freezing and thawing that is common on the plateau - foreground of shot
The 'terracing' (layers of gravel & vegetation) caused by freezing and thawing…
(Photo: E. Rodewald)