Geese, Ducks and Coots

Canada geese, snow geese, ducks, and American coots all have been implicated in agricultural crop and turf damage. Canada geese and snow geese that graze on winter wheat and rye crops can reduce subsequent grain and vegetative yields. Canada geese also cause serious damage to sprouting soybeans in spring and to standing cornfields in the autumn. The most common damage to agricultural resources associated with geese results from consumption of crops. Other impacts involve unacceptable accumulations of feces in pastures, trampling of emerging crops, and increased erosion and runoff from fields where the cover crop has been grazed. Canada geese graze on a variety of crops, including alfalfa, barley, beans, corn, soybeans, wheat, rye, oats, spinach, and peanuts, sometimes resulting in significant reductions in yields. Since the dramatic increase in snow goose populations, there has been extensive damage to their breeding habitat in the in the Arctic and tremendous grazing pressure on exposed crops and vegetation during the early spring migration. Most damage results from grubbing, trampling, and uprooting and occurs along the migration route on the eastern coastal areas, and in the mid-western and southern states. In addition, agricultural producers are concerned that geese spread noxious seeds to crop and pasture lands and reduce livestock forage. During the fall, winter, and early spring, large flocks of ducks and American coots migrate into California where they damage small grains and alfalfa. Most damage is from grazing on alfalfa or sprouting grain. In the fall, large flocks of ducks and American coots alighting in un-harvested rice fields trample and consume the crop. Prior to the 1990s, ducks and geese had been reported to cause as much as $6 million to$10 million in damages to grains that are swathed and laid on the ground before harvesting. Most of this damage occurred in the Canadian Provinces and Dakotas. However, changes in harvesting techniques in the 1990s from swathing to straight- or stripper-cutting have greatly resolved the problem. Migratory Canada geese, ducks, and American coots on their winter range have become acclimated to urban environments where they graze on domesticated grasses in parks, golf courses, highway rights-of-way, sport fields, and similar locations. Damage and economic costs at these locations varies by species, numbers, and concentrations, but can be substantial. For example, damage to putting greens by geese, ducks, or coots can cost thousands of dollars to repair or replace

An Overview of Current Blackbird Research in the Southern Rice Growing Region of the United States

Red-winged blackbirds (Agelaius phoeniceus), common grackles (Quiscalus quiscula), and brown-headed cowbirds (Molothrus ater) cause extensive damage to newly planted and ripening rice. The blackbird-rice problem has generated considerable public pressure in states such as Louisiana, Texas, California, Arkansas and Missouri, to find more effective methods of reducing damage caused by blackbirds. USDA/ APHIS/WS National Wildlife Research Center (NWRC) works closely with various state rice growers associations and the USDA Wildlife Services (WS) state operational programs to address this high-priority issue. NWRC conducts a multi-faceted research program aimed at resolving blackbird-rice problems. Research focuses on determining the status of depredating species in southern rice growing states, assessing the impact of birds on production, evaluating and developing potential bird repellents, improving the effectiveness of DRC- 1339, and developing new strategies and/or tools to manage bird damage to rice

Downwash in Vortex Region Behind Rectangular Half-wing at Mach Number 1.91

Results of an experimental investigation to determine downwash and wake characteristics in region of trailing vortex system behind a rectangular half-wing at Mach number 1.91 are presented. The wing had a 5-percent thick symmetric diamond cross section beveled to a knife edge at the tip. At small angles of attack, downwash angles were in close agreement with predictions of linearized theory based on the assumption of an undistorted vortex sheet. At higher angles of attack, the flow was greatly influenced by the rolling up of the vortex sheet

Field Evaluation of a Visual Barrier to Discourage Gull Nesting

Expanding gull populations along the Columbia River have been implicated in depredations to threatened and endangered migrating salmon smolt, depredations to agriculture crops, bird-aircraft strike hazards, nuisance problems, and potential threats to public health. In an effort to develop management methods for controlling gull populations, we tested a visual barrier to discourage gulls from nesting on an island in the Columbia River. The barrier material is a woven black polypropylene fabric that we utilized to take advantage of the gulls\u27 innate predator avoidance mechanisms, by removing their line of sight to approaching terrestrial predators while providing no protection from aerial predators. The visual barrier was installed on Upper Nelson Island, Benton County, Washington, in a 70 x 70 m area composed of parallel rows spaced 5 m apart. Gulls used 87% of the 7.9 ha island as nesting habitat and we estimated \u3e21,000 gull nests, 80% Ring-billed Gull and 20% California Gull nests. However, Ring-billed Gulls occupied only 38% of the nesting territory, while California Gulls occupied the remainder. The treated and control zones occupied about 12.3% of the gull nesting habitat on the island. The area with fencing had 84% fewer nests than the control area. Silt fencing has potential as a nonlethal bird management technique in certain situations and should be further evaluated as a nesting deterrent

Field evaluation of a visual barrier to discourage gull nesting

Expanding gull populations along the Columbia River have been implicated in depredations to threatened and endangered migrating salmon smolt, depredations to agriculture crops, bird-aircraft strike hazards, nuisance problems, and potential threats to public health. In an effort to develop management methods for controlling gull populations, we tested a visual barrier to discourage gulls from nesting on an island in the Columbia River. The barrier material is a woven black polypropylene fabric that we utilized to take advantage of the gulls\u27 innate predator avoidance mechanisms, by removing their line of sight to approaching terrestrial predators while providing no protection from aerial predators. The visual barrier was installed on Upper Nelson Island, Benton County, Washington, in a 70 x 70 m area composed of parallel rows spaced 5 m apart. Gulls used 87% of the 7.9 ha island as nesting habitat and we estimated \u3e21,000 gull nests, 80% Ring-billed Gull and 20% California Gull nests. However, Ring-billed Gulls occupied only 38% of the nesting territory, while California Gulls occupied the remainder. The treated and control zones occupied about 12.3% of the gull nesting habitat on the island. The area with fencing had 84% fewer nests than the control area. Silt fencing has potential as a nonlethal bird management technique in certain situations and should be further evaluated as a nesting deterrent

Longevity of Dayglo Fluorescent Particle Marker Used to Mark Birds in Flight Pen and Field

Spray application of fluorescent particles is a widely used and very valuable technique for marking birds. This remains one of the few practical means to mark large numbers of birds for monitoring movement, despite recent availability of a variety of more technologically advanced options. We monitored the longevity of the DayGlo fluorescent particle marker on red-winged blackbirds under simulated field conditions in a flight pen, and in an observational field experiment. In the pen study we banded 52 red-winged blackbirds with individually numbered leg bands, and sprayed them with DayGlo fluorescent particle marker from a distance of ~50 cm, on 1 December 2004. These birds were recaptured and DayGlo fluorescent particle marks assessed 11 times until 10 August 2005. All 31 surviving birds at the conclusion of the study (i.e. after 254 days) retained at least some DayGlo fluorescent particle marker on one or more body regions. Wings retained DayGlo fluorescent particle marks longer than other body regions and thus could be used to identify marks in large-scale collections. Roosting wild blackbirds aerially marked in September and October 2005 retained marks through June 2006, 263 days after marking. The formulation used is inexpensive (US$4.00 L-1), easy-to-apply at many scales and practical for many species (e.g. starlings, blackbirds, sparrows, gulls and shorebirds)

Hazing and Movements of Canada Geese near Elmendorf Air Force Base in Anchorage, Alaska

Bird strikes to aircraft are a serious economic and safety problem in the United States, annually causing millions of dollars in damage to civilian and military aircraft and the occasional loss of human life. We observed movements of 1236 neckbanded lesser Canada geese (Branta canadensis parvipes) to determine efficacy of hazing as a means to reduce goose presence at Elmendorf Air Force Base (EAFB), Anchorage, Alaska from August to October 1997. Emphasis was on movements of geese onto EAFB with additional data collected at the other two major airports in the area, Anchorage International Airport (AIA) and Merrill Field Airport (MFA). Daily observations indicated the presence of 208 individual neckbanded geese on EAFB, and 20% returned more than once after being hazed from EAFB. We identified three staging areas, geese utilized prior to entering EAFB, and three post-hazing dispersal sites. Collared geese began moving onto EAFB 30-40 days post-molt with the largest proportions moving onto EAFB 70-90 days post-molt. We observed 75 neckbanded geese on AIA from seven molting sites, and 23% returned more than once after being hazed from AIA. We observed 141 neckbanded geese on MFA from 14 molting sites, and 21% returned more than once after being hazed from MFA. Our data indicated that as long as local goose populations increase, large numbers of Anchorage area geese are likely to enter one of the airports creating a variety of management problems. Hazed geese returning to airports multiple times present a special hazard to aircraft safety because they appear to have become habituated to non-lethal scare tactics. We recommend an integrated management approach to limit the Anchorage area goose population utilizing various control techniques which are acceptable to Anchorage residents while continuing the hazing program at area airports

Efficacy of Translocation of Red-tailed Hawks from Airports

Raptor translocation from airport environments is a management strategy that has been recommended and used in attempts to reduce aircraft strikes. However, supportive data are lacking about optimal translocation distance and direction, return rate, post-translocation fate and overall efficacy of the technique. We conducted a study from 1 December 1999 to 28 February 2002, which included satellite telemetry, to address these issues of raptor translocation at a Midwest Airport. Two hundred and fourteen red-tailed hawks (Buteo jamaicensis) were translocated to 12 sites in Illinois, between 59 and 242 km from the airport. Thirty-four after-hatch-year (AHY) individuals were fitted with satellite (PTT, n = 22) or VHF (n = 12) transmitters. As of 31 October 2001, 34 (15.9%) of the 214 red-tailed hawks returned to the airport. We compared the return rate among age class, period of translocation (i.e., breeding, fall and spring migrations, and over wintering), direction of translocation, and translocation distance. Only 3.2% (3 of 93) of hatch- year (HY) individuals returned, whereas 25.6% (31 of 121) of AHY birds returned (P \u3c 0.001). HY red-tailed hawks were also easiest to capture and least likely to return. No differences among the other factors were identified. The mean number of days to return was 108.6, range 2-369. Satellite data indicated that 19 of the 22 (86.3%) PTT-fitted birds dispersed from the release site within 5 days, suggesting that translocation did not result in an over-saturation of individuals at the release sites. Use of airport habitats by PTT-fitted birds was significantly different (P = 0.009). However, this was probably due to a single individual being relocated on airports 43 of 125 times (34.4%). Excluding this individual eliminated statistical significance (P = 0.576). Although PTT-fitted birds used airport habitats greater than expected, average use was extremely low, \u3c2%

Ariel - Volume 7 Number 2

Editors Mark Dembert Frank Chervanek John Lammie Jim Burke Curt Cumming