Ronald M. Case

Influences of Trees on Abundance of Natural Enemies of Insect Pests: A Review

In this article we review the use of natural enemies in crop pest management and describe research needed to better meet information needs for practical applications. Endemic natural enemies (predators and parasites) offer a potential but understudied approach to controlling insect pests in agricultural systems. With the current high interest in environmental stewardship, such an approach has special appeal as a method to reduce the need for pesticides while maintaining agricultural profitability. Habitat for sustaining populations of natural enemies occurs primarily at field edges where crops and edge vegetation meet. Conservation and enhancement of natural enemies might include manipulation of plant species and plant arrangement, particularly at these edges; and consideration of optimum field sizes, number of edges, and management practices in and near edges. Blending the benefits of agricultural and forestry (windbreak) systems is one promising approach to field edge management that has additional benefits of wind protection and conservation of desirable wildlife species.

Diet and Nesting Success of Barn Owls Breeding in Western Nebraska

-We analyzed the diet of barn owls (Tyto alba) in Lincoln County, Nebraska during nesting seasons of 1984 through 1986 and their nest success in 1985 and 1986. Nesting attempts were made at 9 of 13 nest sites checked in 1985 and at 12 of 15 nest sites in 1986. Microtus ochrogaster comprised 32.7% of 10,140 prey items overall with marked increase in percent from 1985 to 1986. Barn own reproduction increased from 1985 to 1986 with more nests initiated, a higher proportion of successful nests and higher mean number of young fledged per nest attempt. Proportions of prey in the diet were significantly different from proportions of prey captured by trapping. Microtus ochrogaster was overrepresented and Peromyscus maniculatus underrepresented in the diet. Annual percentages of M. ochrogaster and Perognathus hispidus in the diet were negatively correlated with Reithrodontomys megalotis and with P. maniculatus but were not correlated with each other. Reithrodontomys megalotis and P. maniculatus were not correlated with each other. Reithrodontomys megalotis decreased and P. hispidus increased in the diet each year. A number of factors influence barn owl reproductive success including diet, quality of nest site and foraging ability of

Assessment of Squirrel-Caused Power Outages

Squirrel-caused power outages in Lincoln and Omaha, Nebraska, were evaluated by examining company power outage reports and by consulting with power company representatives. Reports showed that squirrel-caused outages at pole-mounted transformers were most prevalent during May, June, and October (48% of total) and between 1 and 4 h after sunrise (38%), patterns that coincide with squirrel dispersal or morning activity periods. In Lincoln, 1980 and 1981, squirrels caused 177 outages per year, which was 24% of all outages and 90% of animal-caused outages. Estimated minimum annual costs were

Biodeterioration of the biosphere: where does wildlife damage management stand?

23 364 for repairs, public relations, and lost revenue while meters were not running. In Omaha, 1985 and 1986, squirrels caused 332 outages per year, costing at least

Agroecology of Birds in Organic and Nonorganic Farmland

47 144 annually. Squirrel-caused outages at substations cost an additional

Characteristics and Distribution of Coyote X Dog Hybrids Collected in Nebraska

400 (Lincoln) to

Surplus-Killing by Coyotes

810 (Omaha) annually. Between 1982 and 1985, squirrel guards were installed on all 13 000 Lincoln transformers at an estimated minimum cost of

WILDLIFE AS NATURAL ENEMIES OF CROP PESTS

20 per guard, or

Great Plains Wildlife Damage Control Workshops

260 000 total. Records from Lincoln after all guards were installed (1986 and 1987) indicate that annual costs were reduced 78% to

Trees on the Great Plains: Agro-Ecosystem Diversity

5148. Life expectancy of the guards is unknown. The extent of squirrel-caused outages and associated costs may vary among cities and regions. Assessment of these outages as described here can be used for timing biological studies and as a procedural structure for making similar economic assessments in other areas.