Want to know state of the planet? Count penguins

Satellite imagery and software has sped up NZ's annual census of Adelie penguins around the Ross Sea region of Antarctica. Photo / Phil Lyver, Landcare Research

Two hundred thousand and one, two hundred thousand and two, two hundred thousand and three ...

It might not be that simple, yet the soon-to-begin annual job of counting every Adelie penguin in the western Ross Sea region of Antarctica can be a process almost as slow as the birds themselves.

As key indicators of climate change, penguins serve a crucial role for scientists examining what fluctuations in the white continent mean for the rest of the world.

New Zealand is responsible for the annual census of the penguins in this area, counting one adult in each of the breeding pairs every season on their three colonies - Cape Crozier, Cape Bird, Cape Royds and Ross Island.

Each year over the past three decades, the overall population has numbered around 240,000 pairs, just over a quarter of the Adelie penguins that breed in the Ross Sea region and around 10 per cent of their global population.

For the past 30 years, this was done by counting the penguins from photographs. But in the past three years, specially developed semi-automated software has sped up the process immensely.

A helicopter platform was used to photograph colonies on Ross Island, and on Beauford Island when sea ice extended that far. A C-130 Hercules was needed to reach colonies spread out over 1000km further up the Victoria Land coast.

More recently, satellite imagery has been used to conduct an Antarctic-wide census of Adelie penguins, said Landcare Research ecologist Phil Lyver.

The technology had also been used to discover Adelie penguin colonies for the first time.

Dr Neil Gilbert, Antarctica New Zealand's environment manager, said keeping long-term datasets could allow scientists to track fluctuations in food source and habitats, or changing temperatures.

"Obviously, penguins are an iconic species when you think about Antarctica, and we want to make sure we understand the populations, because of the value they have in Antarctica, and because our management of Antarctica depends what's going on there," he said.

"The other reason is they are indicators of climate change and we want to understand how Antarctica is going to change, and what the effect of that is going to be on New Zealand and the rest of the world."