Fig. 7. Box plots of hybrid index scores for Canada jay (Perisoreus canadensis) Boreal and Pacific morphotypes in the presence and absence of Engelmann spruce.

For Rocky Mountain morphotypes which are associated with Engelmann spruce, we compared hybrid indices in forests where only Engelmann spruce was found and where Engelmann spruce overlapped with coastal and boreal tree species. Dark lines represent the median and the bottom and top of box represent the 25th and 75th quartiles, respectively, while the whiskers extend to the highest and lowest values. Asterisk above paired plots show comparisons significant at p < 0.05.