Protection of Mountain Apiaries from Bears by Use of Electric Fence

Abstract

Nature often has woven a strange fabric of interrelations between various species of animals and plants in the wild, and nowadays some equally complex situations are arising in the field of economic zoology where the activities of different species of animals touch diverse human interests. Thus, the evolution of agricultural crop production in the lowlands of California has now affected the wild black bears in the Sierra Nevada, and the aid of an electrical engineer was necessary in the chain of adjustments that had to be made! Early crop production in the great central (Sacramento-San Joaquin) Valley of California was chiefly of cereals, as depicted in Frank Norris' novel, "The Pit." In time, the development of the automobile and tractor largely replaced use of horses and mules in transportation and farm operations, and lessened the demand for hay and grain production. Meanwhile, levees and dikes had been built by drainage engineers, confining winter flood waters to proper channels, and a regulated irrigation made fruit and vegetable production more practicable on many rich river bottom lands. Studies in human nutrition had revealed the desirability of greater quantities of fruits and vegetables in the human dietary, and improvements were being made in methods for fresh shipment and for canning these products. In consequence of these and other factors thousands of acres in the Sacramento-San Joaquin Valley are now devoted to commercial production of fruits and vegetables. Bee keeping has increased in the valley as a means of using floral byproducts and also as an aid to cross pollination for fruit trees, but apiarists experience difficulty in maintaining their colonies because the summer forage supply for bees is irregular. The fruit blossoms afford a large supply of pollen and nectar through a brief period in early spring. Annual vegetation provides bee forage until it begins to dry up, ordinarily early in May. Alfalfa and star thistle blossoms are available in late summer. The presence of thousands of acres of single species of crop plants in turn affords a favorable "culture medium" for insects and other pests, and these also have increased and spread. Efforts to reduce or control such pests now involve use of large quantities of toxic chemicals that are dusted on the plants, Some of these substances, especially compounds containing arsenic, are poisonous also to hive bees. Worker bees visiting the blossoms of dusted plants and other blossoms nearby onto which the poison dust has drifted become contaminated with the poison. This is transported with pollen (but not with nectar2) to the hives, where it becomes