Bird species that occurred in only one forest type were deemed
to be forest type specialists and assigned the highest specialization
score, level 4. Those species in more than one forest type but with
significantly greater abundance in one forest type over another (using the D⁄ criterion and visual inspection of the patterns), or
with a significant difference in occurrence (for species too scarce
to make D⁄) are called moderate specialists, and categorized as
level 3. Species associated with two forest types with no marked
difference in abundance (or occurrence, for species where D⁄ is
inappropriate) between the types are called generalists, categorized
as level 2. Finally, those with no significant difference in
either occurrence or overall abundance among the three forest
types we called complete generalists, categorized with a score of 1.