An Adelie penguin on Shirley Island near Casey station, Antarctica. Photo: Colin Cosier
With an ice axe in one hand and a camera in the other, Colin and I join a few Casey locals on a walk to see the Adelie penguins nesting on nearby Shirley Island.
The small, rocky island is connected to the continent for most of the year by sea ice. But come summer, much of the sea ice melts, and we arrive to find only a narrow ice-bridge crossing.
Fairfax's Nicky Phillips and AAD expeditioner Clare Ainsworth on the ice walk. Photo: Colin Cosier
Walking on melting sea ice can be risky, so we each carry survival backpacks with axes, ropes, shelter, water and emergency clothing - just in case anybody is unlucky enough to get wet.
As we near the crossing, our guide, field training officer Tim Gill, takes his axe to the ice, hacking the surface to assess its structural integrity. It's brittle on top, but the layer underneath is sturdy enough to cross.
Fellow walker Clare Ainsworth drives an ice drill into the surface to measure the ice thickness. At one metre she hits the water below.
The penguins react as a skua tries to snag an egg. Photo: Colin Cosier
While it is safe to walk on solid, intact sea ice that is only 20 centimetres thick, some of the ice around us is brown and slushy.
Clare is the first to navigate a safe path to the island. I follow, taking one tentative step at a time. It's eerie to hear the ice creaking underfoot. A few times my boot breaks a newly formed ice crust and plunges a few inches into the slush.
Another walker is unlucky enough to sink knee-deep into the icy mush.
The penguins seem mildly amused by our misfortune. A few are bold enough to come close and gawp.
The Australian Antarctic Division is strict about keeping a distance from the birds, especially when they're breeding. On the island, the penguins congregate on ice-free nooks.
We pick a section of rocks to sit and watch. Most are sitting on their nests, incubating eggs. Others, in the process of building their homes, take any opportunity to steal a neighbour's rocks for their own building material.
A brown skua, a bird that looks like overweight pigeon, attempts to snag an unattended egg. The colony reacts with a loud symphony of squawks.
We head back to station after an hour, taking a new route over the ice bridge. By the time we get back to station, the afternoon Shirley Island walk has been cancelled – the sea ice is too unpredictable.
I'm glad we decided to forgo our sleep-in and take the morning option – we were the last walk this season. The sea ice will detach any day.