Ordination for Body Condition and Cause of Death in Adult Bonin Petrels (Pterodroma hypoleuca) Goal: 1) Develop Body Condition Index (BCI) to describe the body condition of adult Bonin Petrel. 2) Compare cause of death to body condition. Hypothesis 1: Tarsus length or bill depth will have strongest correlation with body mass. Hypothesis 2: Birds that died naturally will have worse body condition.

Morphometric Dataset Main Matrix: Data file: M1PCA.wk1 41 Adult specimen 7 morphometric variables: Mass Culmen Bill Depth Bill Depth at base Head length Tarsus Wing length Head Length Culmen Bill Depth Bill depth at base Wing Length Tarsus

Dataset Processing 1 species was discarded because their wing length was an outlier that fell outside of 2 SDs This outlier was causing a high skewness for “wing length” variable The skewness did not go down after any transformations Once the outlier was removed from the dataset, the “wing length” skewness was normal (-1 to 1) without any transformations Because of this, I have 41 instead of 42 specimen to be analyzed

Data Exploration r = 0.57

Dataset Analysis

Results Interpretation Criterion 1: Broken-Stick Eigenvalue Stop at Axis 1 Criterion 2: Significant p-value

Overall Body Condition Larger mass and bigger bill depth at base is associated with a higher Body Condition Score Mass BD Base Condition 2016-078 219 12.69 9 2015-020 120.5 11.51 1 2016-091 103 10.16 7

Body Condition Index

Cause of Death Smaller birds tended to die from unknown causes Larger birds tended to die from injury

Cause of Death cont. All skinny birds died from unknown causes

Discussion Bill depth at base is a good metric for Standard Growth Rate in creating a Body Condition Index Visual Body Condition Scores strongly correlate with bird mass and bill depth at base All birds that were below the average weight for their size died from unknown (presumably) natural causes This exercise showed me that it is more difficult to draw conclusions from binary data

Next Steps MRPP will be used to test for grouping differences of both Body Condition Scores and Cause of Death The next step is to apply these techniques to chick data to look for similarities and differences between these two groups Once a Body Condition Index is established for both age classes, I will include data on plastic ingestion to compare plastic incidence and mass to body condition of the birds