This week at Macquarie Island: 1 June 2018
This week at Macca we feature our winter breeding grey petrels and the Nissen hut, a stalwart of station buildings
Fifty shades of Winter greys and counting
The Australian Antarctic Program is supporting post-eradication monitoring to assess how Macquarie Island’s wildlife is recovering following the removal of invasive pests in 2011-2014.
After the productivity of summer, island life has slowed right down. As the landscape has turned from green to brown, many of the species this project is studying have left, but they’ve been replaced by winter-breeding Grey Petrels. Preyed upon heavily by cats, these beautiful seabirds went extinct on Macca during the 20th Century, but began to recolonise in the late 1990s when the last cats were killed.
All seabirds play a hugely important role transferring nutrients from sea to land where their guano enriches island soils. As a result, the tussock grass growing in seabird colonies is especially lush and nutrient rich - qualities which made it particularly palatable to rabbits. When the rabbit population exploded on Macquarie in the early 2000s, the vegetation in seabird colonies was heavily grazed and these areas became denuded. This destabilised soils with devastating impacts for burrowing seabirds - burrows collapsed as soils washed away. Owing to these threats Grey Petrels are listed as Endangered under Tasmanian State legislation.
All of this is now thankfully in reverse. The number of Grey Petrel burrows monitored by the Tasmania Parks and Wildlife Service has increased year on year, and the tussock grass they’re found in is once again tall and lush. So much so, it is now increasingly impenetrable, criss-crossed by a maze of tunnels at ground-level which the birds keep open as access roads to their nesting burrows. Many of the island’s petrel colonies are safeguarded within Special Management Areas so we rarely witness the drama within.
By day they are tranquil, but at night they come alive as birds return from sea. The rapid regrowth of the island’s vegetation, and the nocturnal behaviour of seabirds at their colonies present real challenges for monitoring their recovery into the future. Coupled with a desire to minimise disturbance within colonies, this is driving the development of new approaches to monitoring using emerging technologies.
At Macquarie we’re using remote microphones to record the night-time cacophony of noise as breeding birds hose their songs into the night from perches atop tussock heads, and remote cameras are observing the comings and goings of birds from the colony. These are designed as low cost, low impact ways to set baselines, and monitor population changes into the future.
By Jez Bird, PhD student with the University of Queensland, supported by a scholarship under the Research Training Program, and AAS Project 4305.
The role of the Nissen Hut at Macquarie Island - Part 1
The humble Nissen Huts have a lot history.
Part 1 of this 2 part series, will illustrate and discuss the role the Nissen Hut has played on Macquarie Island since 1952 to the present day.
The huts were designed by a Canadian, Lt. Colonel PN Nissen. Lt. Colonel Nissen had several careers based on the opportunities that came his way in the early 1900’s. He is recorded as being an adventurer and an inventor.
The first huts were built during the First World War and by the end of 1918 an estimated total of some 100,000 huts had been built in many variations and serving a multitude of purposes. The technical features of the hut were suitable for the military requirements during the campaigns of WW1, but how did they fit into the design requirements of Macquarie Island?
There are many factors that made the Nissen Hut an important part of the ANARE (Australian National Antarctic Research Expedition) for the sub-Antarctic islands of Heard Island and Macquarie Island.
- The huts were surplus from the 2nd World War – very low cost.
- ANARE had a good working relationship with the armed forces.
- The individual components of the hut were pre-fabricated and were of minimal shipping bulk, allowing greater storage room on the ships.
- The huts were relatively simple to erect and the speed of erection allowed them to be completed in the often difficult weather conditions, by unskilled personnel.
- The barrel vault design provided great strength, was very simple and provided a large enclosed space in proportion to the required building material.
- The huts have been very successful over the last 70+ years, but there are a few major flaws in their use on the sub-Antarctic islands.
- Bracing was not considered sufficient for the weather conditions on the islands.
- The hut materials were very prone to the salty conditions and corrosion. Especially the use of early galvanised iron cladding.
- The huts had no insulation (mainly due to the huts being designed for drier and warmer locations) and were very difficult to heat and keep free of condensation.
The records and photos available (Thanks Chris H.) indicate that there were a total of at least seven Nissen Huts built on Macquarie Island from 1952 to 1969. They were used primarily as stores huts for each of the trades, meteorology and science disciplines.
Stay tuned for Part 2 next week with more recent photographs and information the Nissen Huts still play in 2018.