Fig. 2.

Box plot of bill lengths of male and female A.mantelli on Ponui Island compared with depths of probe-holes found in Red Stony Hill Gully. Probe-holes deeper than maximum bill lengths of kiwi are opened by birds working to create a large hole into which the face is partially inserted (S. Cunningham pers. obs). ⊕ = mean length/depth. Boundaries of boxes indicate the interquartile range. Dividing line within each box indicates the median, whiskers indicate the range excluding outliers. Outliers are indicated by * and are calculated as data points falling beyond 1.5× the interquartile range outside the upper and lower quartiles.