Honeybee pollen loads were trapped from hives at five sites in LaCrosse County, Wisconsin, USA, throughout one season. The percentages from different plant species were determined. The season could be divided into three parts: tree sources from early April to late May, then shrubs until mid-June, followed by herbaceous plants until the end of September. An unexpectedly large amount of the pollen came from wind-pollinated species, especially oak (Quercus sp.) and corn (Zea mays).