At Cape Royds we watch to see what the adults are feeding their chicks. If it is pink, then the main portion of the food is krill, if it is silver then it is fish. But what kind of fish? That is where the penguin poop tray comes in. At the end of last season we set out a large tray with a fine mesh in an area where penguins have regularly nested. After the breeding season was over and the nesting adults and chicks were gone, the tray was full of penguin guano. Several washings and sortings to eliminate the large stuff later, we sift through the rest looking for otoliths (fish ear bones) which will tell us what kind and how old the fish is. The bones do not get digested so they are passed through. It’s messy work, but important knowledge to gain about Adelie Penguins and their eating habits.

A new otolith tray set out in the field waiting for penguins to make their nests.

Luckily two penguins decided to nest in the tray. Lots of guano for us.

A season’s tray of penguin guano washed and sieved and ready for sorting under the stereoscope.

Now the work begins. It takes hours to look for the tiny bones.

An otolith, less than a millimeter long.