Jerrold L. Belant

Gulls in urban environments: landscape-level management to reduce conflict

Abstract Populations of several species of gulls ( Larus spp.) have increased dramatically throughout coastal areas of North America and Europe during the past several decades. These increases have been attributed generally to protection from human disturbance, reduction in environmental contaminants, availability of anthropogenic food, and the ability of gulls to adapt to human-altered environments. Gull abundance in urban areas has resulted in numerous conflicts with people including hazards to aircraft, transmission of pathogens and parasites through contamination of water sources, damage to buildings from nesting material and defecation, and general nuisance. Various architectural and habitat management approaches presently are available to reduce gull/human conflicts. For example, gull use of putrescible-waste landfills may be reduced by covering refuse, diverting anthropogenic food to covered compost facilities, erecting wire grids over exposed refuse, and manipulation of turf height in loafing areas. Nesting on roofs can be alleviated through modifications of roofing substrate, reducing the number of roof structures present, and placement of overhead wires. Also, attractiveness of airports to gulls can be reduced through drainage of temporary water and by decreasing the availability of prey and loafing sites through habitat management. Architectural design and characteristics of adjacent habitat should be considered during the planning stages of new facilities in areas where use by gulls is likely. Although control activities can be effective at the site where the gull problem occurs, uncoordinated management efforts may cause relocation of the problems to surrounding areas. Also, site-specific management will rarely solve the problem across a larger scale (e.g., city-wide). A working group comprised of the respective city or county planning commission, affected businesses and other government agencies, private citizens, and wildlife professionals could be formed to provide overall direction for gull management. This working group would define the extent and nature of the problem, develop an appropriate management strategy incorporating ecology of the nuisance species, and conduct periodic assessments of program efficacy. An integrated, landscape-level management approach is necessary to ensure an overall reduction in conflict between gulls and people in urban environments.

Evaluation of propane exploders as white-tailed deer deterrents

Abstract In response to increased white-tailed deer (Odocoileus virginianus) depredation of agricultural crops and encroachment on airports, we evaluated the effectiveness of systematic and motion-activated propane exploders as deer frightening devices. We conducted three experiments in a 2200 ha fenced facility in northern Ohio with high (91/km2) deer densities during 1994–1995. Systematic exploders were calibrated to detonate once at 8 to 10 min intervals, whereas motion-activated exploders detonated 8 times/deer intrusion. Systematic propane exploders were generally ineffective, deterring deer from corn for ⩽ 2 days only, whereas motion-activated exploders repelled deer for 0–6 weeks. Repellency of motionactivated exploders varied seasonally, possibly in response to variations in deer density, availability of alternate food, or reproductive and social behavior. We recommend motion-activated exploders over systematic exploders as deer frightening devices for crop damage mitigation and on airports; however, systematic exploders may have utility for short-term (a few days) use.

Comparison of four particulate substances as wildlife feeding repellents

Abstract We compared the effectiveness of dolomitic lime, activated charcoal, Nutra-lite (a silica-based compound), and white quartz sand as feeding repellents for brown-headed cowbirds (Molothrus ater), white-tailed deer (Odocoileus virginianus), and Canada geese (Branta canadensis). In 4 day, two-choice aviary tests with cowbirds, consumption of treated millet (1–4% g g−1) was less than consumption of untreated millet for all particulates except Nutra-lite at 1% g g−1. Greatest reductions in consumption occurred with lime-treated millet, followed by charcoal, Nutra-lite, and sand. Overall mean daily consumption of treated millet by cowbirds in one-choice tests was similar to total consumption of millet in comparable two-choice tests for each particulate. However, millet treated with 4% lime reduced cowbird consumption for 1 day. Similarly, in 4 day, two-choice field tests involving free-ranging deer, deer consumed less corn treated (4% g g−1) with lime or charcoal than corn treated with Nutra-lite or sand. Corn treated with sand did not reduce consumption by deer relative to untreated corn. Lime applied to turf in 10 m × 21 m enclosures at an application rate of 270 kg ha−1 did not suppress grazing by geese. Nutra-lite applied to turf at the manufacturer-recommended rate of 2568 kg ha−1 reduced overall goose presence on treated plots in enclosures for 3 days but suppressed goose grazing for 1 day only. We conclude that lime is more effective overall as a white-tailed deer and brown-headed cowbird feeding repellent than is charcoal, Nutra-lite, or sand. Lime has considerable potential as a feeding repellent in agricultural and possibly turf situations. Charcoal could be used effectively in situations where lime is impractical.

Methyl anthranilate formulations repel gulls and mallards from water

Abstract Two formulations of methyl anthranilate (MA), one (ReJex-iT™ TP-40 [TP-40]) containing a surfactant, the other (ReJex-iT™ AP-50 [AP-50]) a miscible, free-flowing powder, effectively repelled captive mallards (Anas platyrhynchos) from pools of water in pen tests, and/or free-ranging gulls (Larus delawarensis and L. argentatus) from pools of water in field trials for 4–11 days. With one exception, pool entries and bill contacts with water were reduced (p ⩽ 0.02) in pools treated with both formulations compared with untreated pools. Overall gull activity was reduced (p ⩽ 0.01) when all available water was treated with AP-50. Effectiveness of TP-40 ( v v ) was similar to the previously reported effectiveness of powdered formulations where MA concentrations were 1.6–3.0 times ( g g ) greater, a consequence of the surfactant concentrating MA at the surface. These tests indicate that MA-based formulations might have utility at airports and perhaps other locations where it is desirable to reduce bird activity in temporary pools of water.