Interpreting songbirds overlap

Overlap results consist of histograms for each statistic and a summary table.

There are two alternative hypotheses in overlap statistics, either boundary association or boundary avoidance.

Statistic	Meaning	Overlap	Avoidance
OS	the number of Boundary Elements (BEs) in both sets of boundaries	high	low
OG	directional overlap, association of G (birds) with H (vegetation)	low	high
OH	directional overlap, association of H (vegetation) with G (birds)	low	high
OGH	simultaneous overlap, association between the boundaries	low	high

Histogram

The warbler boundary is "G". Overlap would be indicated by high values of OS (significant upper p-value) and low values of OG, OH, or OGH (significant lower p-value). Low values of OS and high values of OG, O H, or OGH indicate spatial avoidance between the two boundary sets.

The histograms show the values for these statistics from Monte Carlo randomizations of the boundaries. The observed overlap values are shown as a red bar on the histogram. Viewing the histograms allows you to visually assess how unusual the observed values are compared to the randomizations.

Although individual results may vary (because of the randomizations), on average the observed values of OS, , OG, and OGH fall in the middle of the distributions; they are not remarkable. The value for OH shows significant boundary avoidance. This result can be in part explained by the fact that there are more vegetation boundaries, so some of them are not at all near songbird boundaries.