Figure 4.

Experimental maze used to investigate olfactory orientation towards the burrow in Antarctic prions (A) and results of the choice tests performed in a variety of conditions (B). A. A flexible T-maze was located in front of two burrows and the end of one arm was connected to the entrance of the burrow of the bird being tested while the other arm was connected to the entrance of a neighboring burrow. In control experiments, the same maze was used and placed in front of burrows but the end of each arm was closed so that no olfactory stimulus could be detected in the maze. B. Results of these maze orientation experiments performed in a variety of conditions: birds were either untreated (left) or were made anosmic by injection of zinc sulphate in the olfactory chambers (middle) or were tested in a control situation in which the end of the arms were closed so that olfactory stimuli from the burrows could not enter the maze (right). Black= choice of the correct arm leading to the nest, Light grey= wrong choice (neighbor’s burrow), Dark grey = no choice. Redrawn from data in Bonadonna et al. (2003b).