Written by Chrissy Wickes
“The penguin work we did was another data point for the EC and RH populations building on the 2011 survey.” said Jo Hiscock. “The reason for doing it again so soon was to see what effect the slips had had on the populations. Initial surveys (a few hours circumnavigating the island) suggested that up to 20% of the colony areas had been affected by these natural slips. These were the same slips that had caused the hut to be pushed off its foundations. Our estimate of when the slips occurred are around the 6th January 2014, which would have meant that chicks would have still been in the colonies. That season’s cohort of chicks is likely to have been severely affected but we had no idea how it might have affected the breeding population not knowing how many adults would have been in at the time. Seeing that a trip was planned as part of the Antipodes Island Mouse Eradication project, we thought we would join the team and follow up with another count.
We were a bit short on time as everything takes longer than you think when you are living out of a tent and the hut has turned into a building site. Also we donated a capable penguin counter to the hut rebuild team! We managed to get most of the ground counts done so they are directly comparable to previous surveys.
I warned the team that the MOAC (Mother Of All Colonies) on the south coast was going to take a few big days of work and be hard yakka – it lived up to expectations with strong southerly squalls and snow falls. The southerly persisted for the 4 days that we camped out down there doing the south coast penguin counts!
Erect Crested Penguin nests had been counted island wide in 2011 and after the 2014 slips, were recounted with results showing a 10% decline in nest numbers in areas counted where slips affected colonies. However, even in areas where slips did not affect colonies nest numbers were down 10%. Penguins are notorious for yearly variation in breeding and nesting numbers. Although these declines look significant, there are many other variables that need to be considered. So we cannot assume that the number of nests have decreased by 10% as a result of the slip event alone, however it is certain to have been a contributor. The 10% decrease in non-slip affected colonies also needs consideration. For all colonies, it is possible that penguins that were affected by slips in one area may have moved colonies (boosting the non-slip colony figure), pairs affected by slips last year may have had this year off breeding, or at sea, conditions may have caused a lower number of breeding attempts this year compared with last. There are always multiple aspects to consider. For the Rock Hopper Penguin there was no change from the 2011 and the 2014 counts. We are obviously still working on teasing out the data to understand the results.”
Last summer Jo went from Ushuaia (Argentina) to Antarctica and back to Bluff (New Zealand) via the Subantarctic Islands as a Department of Conservation representative on board the Ortelius for Oceanwide Expeditions.
This woman lives most of her summers on islands in the Southern Ocean!