Sediment Traps

At the end of each season when the penguins have left to their colonies and the ground has not frozen yet the bird science group collects the rocks from their "sediment traps". The sediment traps are fine mesh screens that hold the preferred nesting rocks for the penguins with the hope that the penguins will build a nest near or on top of the trap. The mesh and rocks hold on to a breeding seasons worth of penguin colony poo.

The bird scientists collect these rocks and scrape the guano from the mesh into five gallon buckets and bring them back to station. The rocks are then scrubbed clean to remove all the guano. The resulting hot chocolate like mixture is then slowly decanted. A hose in the bucket on low will slowly allow the stinkier bits to float away while retaining the heavier items at the bottom of the bucket. 

What is left at the bottom of the bucket is then dried out and sorted through under a microscope. Most of the detritus left at the bottom of the bucket is smaller rocks, crushed bits of egg shell, and fish bones.

In these samples they bird scientists look for fish ear bones call otoliths and parts of squid beaks. This way they can see what the birds have been eating and feeding their chicks over the course of the whole season.

Fish otoliths are particularly interesting because each species of fish has a different shape of bone. The "rings" of bone as seen above can also be read like tree rings to tell you the age of the fish the bird ate. 

The bird scientists collect these fish bones from several other passive sources as well as from the penguin poop rocks. Here is what a bunch of fish bones look like. 

The clean rocks are then put back into the field for next year. They look a bit like a gross modern art installation.