Over the last week Albatross Researchers, Jaimie and Anna have trekked the whole island in an attempt to say goodbye to every albatross and petrel before resupply… and madly finish off their fieldwork! This week’s task included completing the Southern Giant Petrel (SGP) census. The census involved revisiting colonies all over the coastal flats of Macquarie Island that had been identified with nesting adults in November and then counting the number of chicks remaining to establish breeding success. At around 100 days old the chicks fledge and head out to sea for the first time looking for food. In their first few months at sea they can travel phenomenal distances. Last season a chick that had fledged from Macquarie Island was found on a beach in Chile, South America a few months later! Satellite tracking of fledglings departing Macquarie shows that this could be a common movement with several birds travelling to the west coast of South America.
There are two different colour morphs of SGP on Macquarie Island; a dark morph and a pure white morph. The darker morph individuals are distinguished from Northern Giant Petrels by the colour on their lower bill tip, being green for SGPs and red for NGPs. While white morphs are generally less numerous in colonies than dark morphs, Macquarie Island has an unusually high proportion of white morphs compared to any other colony in the world.
Thank you to the TasPAWs Rangers, Paul and Rich for their assistance in the census.
The very last responsibility of the Albatross girls this season was to band all the albatross chicks within eight study sites before leaving the island. Identification banding of albatross on Macquarie Island is extremely important for establishing survival trends of each of the four species. Jaimie and Anna spent the last two weeks travelling all over the island and ended up banding nearly 150 chicks most of which were on the steep escarpment! With the removal of grazing rabbits, the the thick tussocky vegetation at these albatross sites is returning to its former glory. It is anticipated that this will help increase albatross chick survival giving them greater protection from the weather and their natural predators. We hope to see these chicks back at Macquarie Island in four to seven years when the return to breed for the first time. By Jaimie Cleeland and Anna Lashko
The season is coming to a rapid close and all our scientists are busy collecting, harvesting, sampling, shutting down and packing up before the big orange boat arrives. Lauren, Charles and Josie have completed a large sampling effort to monitor the TPH levels in the soil, ground water and to better understand the microbial dynamics associated with the bioremediation. They are now busy shutting down the lab and preparing the sites for the downsized winter operations. After a huge sampling effort and a mesocosm experiment set up, Grant and Alex are grabbing some last bulk soil samples and invertebrates ready to take back to Macquarie University for further ecotoxicology experiments. The seed collecting aspect of the ecotoxicology project has also been a success, with Corrine managing to collect seeds from 14 species of plants – some of which have only recently ripened their seed. Montia fontana seeds have germinated in the lab indicating that some of the collected seeds are viable. Corrine looks forward to germinating the rest of the collection in the lab at the University of Wollongong once she returns. Brian and Laura have just returned from a busy trip out into the field finalising their vegetation surveys and setting up disturbance plots to establish the ecology of the introduced Poa annua on the island and explore potential management strategies. After an amazingly successful re-discovery trip, locating Galium antarcticum and new populations of Huperzia australiana Jennie and Nick are now planning the final collection of Azorella macquariensis bait samples in an attempt to identify possible pathogens associated with widespread Azorella dieback. Overall It has been a fun and successful science season and we are all now looking forward to meeting, helping, sharing and learning from the round-tripping scientists who are about to embark on Macca over re-supply. By Josie van Dorst
The seed collecting aspect of the ecotoxicology project has been a success. Corrine has managed to collect seeds from 14 species of plants – some of which have only recently ripened their seed. Montia fontana seeds have germinated in the lab indicating that some of the seeds collected are viable. Corrine looks forward to germinating the rest of the collection in the lab at the University of Wollongong once she returns. By Corrine de Mestre