The flowers of most wind-pollinated plants are either male or female. The male flowers produce an abundance of pollen to be carried by the wind. The female flowers usually have large stigmatic areas to receive the pollen. Corn is a good example of a wind-pollinated crop. Birds of several different species feed upon nectar, pollen, or insects in some flowers and serve as pollinators.
None is of significance in pollinating our cultivated crops.
Their visits are confined largely to deep-throated, usually showy wild flowers. Insects of many species visit flowers and pollinate them. These include bees, wasps, moths, butterflies, beetles, thrips, and midges. Bees are the most efficient and the only dependable pollinators, because they visit flowers methodically to collect nectar and pollen and do not destroy the flower or the plant in the process. An estimated 80 percent of our insect pollination is done by bees.