Mawson expeditioners are out in the field, experiencing the best of Antarctic spring and Adélie penguins are counted.

Field travel in spring

It was on the way back from Taylor Glacier, while sitting in the back of the Hägglunds that the thought came into my mind. Greg was at the wheel concentrating on the terrain, trying to pick the best line through the sastrugi and be vigilant about identifying any active tide cracks in the sea ice before we were upon them. We were towing a steel sled so the fact that it doesn’t float like the cab and caboose is compounded when you try to stop quickly on glassy sea ice. It would be easy to find yourself in a skid approaching a tide crack hidden due to being filled with snow. I spoke to Greg over the wireless intercom: “Hey Greg, do you realise that in the last five days we have only been on station for one?” His concentration was penetrated for a second as he let out a big laugh. It’s great being off station in good weather, with good people.

We had just completed the spring census on the longest running science program in Antarctica, Greg had entered the ‘Antarctic Special Protected Area’ (ASPA) the day before with his permit and took photos of the emperor penguins and their chicks for the purposes of an accurate count. Jens and I were waiting around the back of the ASPA perimeter and entered when Greg called to say that he had exited. We successfully installed a new controller into one of the two permanently located cameras.

The 200 km round trip was well lit and there was little to no wind. I must have slept through the few hours of darkness as it was light when I went to sleep and light when I woke in the early hours. There were plenty of Adélie and emperor penguins getting around and lots of Weddell seals, a few with pups around islands and icebergs where the ebb and flow of the tide creates access through the metre thick ice to and from the water.

We considered the Taylor penguin census to be a work trip but just days earlier I was lucky enough to go on a trip to Mt Henderson with Greg and Craig. The three of us travelled by quad to Hendo hut on Saturday after one of Rocket’s famous smokos. Again we had perfect weather with next to no wind and we arrived at the hut with time to have a quick brew and get set to go for a walk.

One of the things that is very hard to gauge or to relay to others is the sheer size and vastness of things down here. The rocks down on the lower plateau within the constraints of the mountain look like pebbles but in fact, when you stand in front of them you realise some are around three metres across and photos can be taken with people in the background completely out of sight. Grounded icebergs on the horizon might be more than fifty kilometres away and would surely be intimidating if you were to stand close enough.

Lucky for us these days we have satellite photographs and electronic maps that we can call upon before such an excursion and with a cheap smartphone, a track can be recorded with speed, distance and elevation and later exported to such electronic maps. Our little walk ended up taking five hours, and we covered eight kilometres, ascending and descending about a vertical kilometre.

Arrival counts

On 15th October the penguin arrival count started. That is, from 15th October we trek out to Bechervaise Island, sit and count the number of Adélie penguins that are present on the island. We continue to count them every second day through to 10 November when we then count them every day.

Initially there are very few penguins. In fact, for the first few counts there were no penguins at all but slowly the numbers increased. From zero to seven to 28 then the numbers jumped to 128 and have continued to climb reaching 960 on October 27th. Numbers are at their highest at the time of peak arrival which is mid-November when we can expect as many as 5000 Adélie penguins.

We continue the count through to 21 November when the arrivals start to level off.

So how do we count them?

Each observer is provided with maps and photographs of penguin sub-colonies, a field book and pencil, a counter and a set of instructions.

Upon arrival the nesting penguins settle into 18 recognised sub-colonies each of which have been photographed, labelled and referenced for our purposes (referenced A through to R). We use the maps of penguin sub-colonies along with photos to navigate to and delineate each sub-colony. We count each penguin in that sub-colony, record it in our notebook and then move on to the next sub-colony.

These sub-colonies are usually discrete with large separation from other sub-colonies, but some sub-colonies are separated from neighbouring sub-colonies by only a small distance and therefore are not so obvious to the person doing the counting.

Two observers undertake the counts each time. They count the total number of penguins within each mapped sub-colony on the island and not confer with each other about their counts until all sub-colony counts on the island are complete. Each observer uses a counter, just as door-person would at a nightclub, and from a vantage point where they have a full view of all of the sub-colonies (which also minimises the need to move around the island and thus minimising disturbance) they click away.

To assist in the counts for when the sub-colonies grow too large the observers use natural features such as rocks and nests or other land features to help break down the large sub-colonies into smaller units to facilitate more accurate counting. It also helps to cast an eye over the sub-colony first and pre-plan how you intend to manage the count before you start. As once you start the count you can’t stop until you have counted every penguin in that sub-colony.

Each observer records their count for each sub-colony in a separate notebook. When all counts on the island have been completed, the two observers compare their overall totals. If the total island counts differ by 10% or less, then the count is complete. If the total island counts differ by more than 10%, identify which sub-colony contributed most to the difference, return to that sub-colony and repeat the sub-colony counts (for example, if one sub-colony had counts of 210 and 260, and another sub-colony has counts of 21 and 26, then the former sub-colony would be recounted because it has the largest absolute difference). If the total island counts now differ by less than or equal to 10%, the count is complete; if not, the sub-colony with the largest absolute difference is again recounted (this might now be a different sub-colony than the previously recounted one), and the process is repeated until the total island counts differ by less than or equal to 10%.

During the arrival count period the penguins are courting and are sensitive to disturbance, so we must keep our movements and voices as slow and low as possible. We never get any closer than what is necessary to facilitate the count.

How do we record and process the data?

As previously mentioned each observer records their count in a separate notebook. These notebooks are labelled ‘Beche arrival counts 2014’. Each count is recorded on a separate page for that particular day where we write the date and the observers name at the top of the page. We also record the letter of the sub-colony ie. A or B etc.

Once the count is complete and both observers have conferred and returned to station, the data is transferred across to an excel spreadsheet.

What do we do with the data?

For our part, nothing. That is we simply wait for the field biologists to arrive on the first voyage of the season who use the data for scientific research.

What exactly does that mean?

Here at Mawson we assist in facilitating many scientific programs with each science program contributing to the Australian Antarctic Division and the Federal Government’s overall scientific direction.

The Adélie penguin counts at Bechervaise Island feed into three such programs. I have listed the public summaries for each of these programs below. Each program is assigned a research number ie. 4086 etc. 

Program 4086

Detecting potential fishery and climate change related impacts through the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR) Ecosystem Monitoring Program. CCAMLR manages the harvest of Antarctic marine living resources so it is sustainable to both harvested and dependent species. The CCAMLR Ecosystem Monitoring Program is one means of achieving this objective. Continuing Australia’s CCAMLR Ecosystem Monitoring Program will serve as a baseline for detecting impacts from a future krill fishery in east Antarctica, provide a tangible indication of Australia’s commitment to sustainable fisheries, extend and add value to the most comprehensive, long term predator monitoring program in the Australian Antarctic Territory, and contribute to the assessment of non-fisheries impacts such as climate change.

Program 4087

Seabird response to environmental variation and change: identifying drivers of key ecological processes. Identifying potential threats from a changing environment on Antarctic seabird populations requires understanding key ecological processes and their driving factors. This project focuses on determining driving factors for seabird demography, phenology, breeding site distribution and foraging habitat. Seabird data will be linked to spatio-temporally coincident data of biological and physical characteristics of the ecosystem to develop explanatory models and, where possible, predictive models to explore the outcomes of plausible scenarios of future environmental change on seabird populations.

Program 4088

Monitoring the status and trends of Antarctic seabirds to improve fisheries. Seabirds are useful indicators of fisheries and climate change impacts in the Southern Ocean. This project aims to develop and apply cost-effective monitoring approaches to determine population status and trends of a suite of seabirds across the Australian Antarctic Territory. Region-wide population estimates will be used to determine seabird prey requirements at spatial scales relevant to fisheries management. The methods and data will contribute to ecosystem-based management of fisheries, assessing climate change impacts, and identifying conservation needs of, and threats to, Antarctic seabirds.

Steve Robertson, Station Leader