710710.fig.002
Figure 2: Difference in mean first arrival dates (±S.E.) of Ruby-throated Hummingbirds in the Central ( ), Appalachian ( ), and Eastern Regions ( ; see Figure 1 for region designations). Arrival days are expressed in “day of year” and corrected for leap years; for example, “130” corresponds to May 10. Inset letters represent differences that are significant at the level.