Appendix E. Seasonal changes in hummingbird visitation to an artificial feeder and weather over a 4-yr period.
Between March 1997 and December 2000, I estimated the seasonal pattern of foraging activity of the hummingbird Sephanoides galeritus by tallying the number of visits to an artificial feeder that consisted of a 10 cm-wide red bowl filled with a 24% sucrose solution. The feeder was located at a site 25 km east of the study plant populations. Observations were conducted every day or every other day during 10-min periods (1–3 periods per day between 0700 and 1900). I recorded air temperature at the beginning of each observation period, and noted whether it was raining or snowing.
FIG. E1. Mean (± 1 SE) visitation by hummingbirds during 30–60 10-min observation periods per month is depicted in the lower panel (solid dots). The climatic variables depicted are mean monthly temperatures (lower panel, dotted line), and number of days with either rain or snow (upper panel, stacked bars).