Port Lockroy Blog #16: Mairi's second penguin update

22/03/2023

We have now completed two all-island surveys of our Gentoo colony here at Port Lockroy, so wanted to provide an update on how they’re doing. 

During the first all-island survey on 12th January 2023, we counted all the nests on the island, as well as all the eggs. In total, we had 529 nests across the island, which means we should have at least 1058 penguins. That’s quite a lot of penguins when you consider that Goudier Island is only around the size of a football pitch! This is around about the same number as normal, which was good to see, after a slow start to the breeding season due to the snow.

It's been a tough season at Port Lockroy for everyone (Credit: Mairi Hilton)

The news on the number of eggs and chicks wasn’t quite so cheerful. There were 588 eggs across the whole island. The last time an all-island egg survey was done was in the 2019-2020 season, before the pandemic, there were 833 eggs.  

During the second all-island survey on the 21st February 2023, we counted 238 chicks and 23 eggs. There had been several big storms between the two counts, and a number of nests had been abandoned. In the 2019-2020 season, they counted 587 chicks, so we have quite a few fewer chicks and eggs than we would hope to see. 

However, as mentioned, the snowfall at the start of the year was challenging for the colony, so we are glad to see that they have still been successful at rearing some chicks! 

Dinner time! (Credit: Mairi Hilton)

The timing of both surveys is around a month later than in a normal year, so it does seem that the snow caused some setbacks. Hopefully, if the weather is less extreme at the start of the next season, the colony should produce more eggs and chicks again. Gentoos can live for up to 20 years, so a few bad years due to bad weather isn’t a major issue for the colony, as long as they get some better weather in future seasons. 

The chicks that we do have are very entertaining neighbours. When they were younger, they looked so out of proportion, in that way that many baby animals do. They had small heads and big bellies and feet we couldn’t believe they would grow into. As such, they were very unstable for a while. 

Chicks have formed crèches (Credit: Mairi Hilton)

A lot of them have now started to form crèches, which are sort of like groups of teenage penguins, running around together. They’re in big groups and are still grey and fluffy but are almost the size of adult penguins. They remind us of puppies in many ways. They seem to get bursts of energy and run around in circles squawking and flapping their little flippers, before collapsing in a heap on the ground and quickly falling asleep. 

They aren’t very discerning about where they sleep either, which has caused us alarm on a few occasions. We’ve seen baby penguins lying haphazardly across the path, only to discover they’re sleeping when we approach closer. 

Relax! This penguin chick is just sleeping! (Credit: Mairi Hilton)

They have an interesting feeding strategy at this stage. The adult will run off, with the chick in close pursuit, only stopping every now and then to feed the chick. This makes for good entertainment, as we watch disgruntled chicks clumsily running after their parent, unsure as to why they suddenly have to work so hard for a meal! This is actually a strategy deployed by the parents to make sure that both chicks get enough food, so it does have a purpose, as well as being fun to watch. 

Some of the chicks are also starting to get their adult feathers. The process seems to start at the top of their head and make its way down, so they have almost adult heads, with the distinctive Gentoo white band across the top, then fluffy grey baby penguin bodies, which is particularly cute.  

An adult Gentoo mounting (Credit: Mairi Hilton)

Many adult penguins are also going through their annual moult. Penguins are one of the few species of birds to grow an entirely new set of feathers at once, rather than gradually replacing them throughout the year as most other species do. They aren’t waterproof at this stage, so are stuck onshore for the entire time they are moulting, which usually lasts around 2-3 weeks. 

Then, they head out to sea and intensely feed for a while before they moult to generate fat reserves, and increase their body weight by over 50%! The moulting penguins look very scruffy and uncomfortable and are often seen staring at rocks or with feathers hanging off their beaks from preening.  

We have one more survey to do before we head home, which will involve counting the number of chicks crèching – we just have to wait until most of them have grown big enough to join a crèche. We’ll be sure to let you know how it goes. 

Mairi Hilton, General Assistant and Wildlife Monitor, Port Lockroy