Use of Confined Dogs for Reducing Deer Damage to Apple Orchards

We assessed the efficacy of free-ranging dogs, confined by buried fences and electronic collars, for reducing deer damage to apple trees in three commercial apple orchards in Oswego County, New York State. During 1995 and 1996, we monitored paired dog-protected and control plots in each orchard. Within dog-protected areas, the percentage of damaged buds was lower, and fruit yield was higher in both 1995 and 1996 than for control plots. Gross economic returns were higher from dog-protected than control plots in both 1995 (by 51%) and 1996 (by 184%). After two seasons of growth, trees planted in May 1995 had nearly three times the cross-sectional area, and were 60% taller if they were in dog-protected rather than control plots. Dogs provided increased economic returns for growers at much lower cost than conventional barrier fencing.

Wildlife Damage to Seedlings in Reforested Hardwood Sites in Mississippi

Herbivory assessments were conducted on seven reforested sites that were less than one year old in the following Mississippi counties: Bolivar, Leflore, and Attala. At each site, 100ft. x 100 ft. plots were established and randomly selected seedlings were marked and measured to determine seedling species, height, condition, survival, and type and extent of animal feeding sign. Surveys were conducted in March/April, May, and August 2004. Herbivory rates were highest during May with approximately 47% of seedlings showing signs of herbivory. In March/April and August, the percentage of seedlings exhibiting signs of herbivory was 37% and 30%, respectively. Foraging by white-tailed deer (Odocoileus virginianus) was recorded on > 90% of the damaged seedlings during each survey. Tree mortality for all study sites and tree species was negligible, with the highest amount (7%) recorded during August, despite the recorded rates of herbivory by white-tailed deer. Herbivory by rabbits (Sylvilagus spp.) and rodents occurred on approximately 6% of the seedlings throughout the 2004 growing season.

BIRD DAMAGE TO TART CHERRIES IN MICHIGAN, 1972

Bird damage to commercial fruits has long been a problem in many coun- tries, but the true magnitude of the damage incurred is difficult to determine objectively. Often the opinions of fruit growers provide the only measure of importance. In 1972, the U.S. Fish and Wildlife Service, the Michigan Department of Agriculture, and the Statistical Reporting Service of the U.S. Department of Agriculture obtained quantitative information on bird damage to tart cherries (Prunus mahalob) in Michigan. The results of the survey are presented in this paper.

Potential Economic Damage From Introduction of Brown Tree Snakes, Boiga Irregularis (Reptilia: Colubridae), to The Islands Of Hawai‘i

The Brown Tree Snake (Boiga irregularis) has caused ecological and economic damage to Guam, and the snake has the potential to colonize other islands in the Pacific Ocean. This study quantifies the potential economic damage if the snake were translocated, established in the state of Hawaii, and causing damage at levels similar to those on Guam. Damages modeled included costs of medical treatments due to snakebites, snake-caused power outages, and decreased tourism resulting from effects of the snake. Damage caused by presence of the Brown Tree Snake on Guam was used as a guide to estimate potential economic damage to Hawaii from both medical- and power outage–related damage. To predict tourism impact, a survey was administered to Hawaiian tourists that identified tourist responses to potential effects of the Brown Tree Snake. These results were then used in an input-output model to predict damage to the state economy. Summing these damages resulted in an estimated total potential annual damage to Hawaii of between $593 million and $2.14 billion. This economic analysis provides a range of potential damages that policy makers can use in evaluation of future prevention and control programs.

SAMPLING OF CORN TO ASSESS BIRD DAMAGE: A Preliminary Review of a Comprehensive Study

"How large a sample is needed to survey the bird damage to corn in a county in Ohio or New Jersey or South Dakota?" Like those in the Bureau of Sport Fisheries and Wildlife and the U.S.D.A. who have been faced with a question of this sort we found only meager information on which to base an answer, whether the problem related to a county in Ohio or to one in New Jersey, or elsewhere. Many sampling methods and rates of sampling did yield reliable estimates but the judgment was often intuitive or based on the reasonableness of the resulting data. Later, when planning the next study or survey, little additional information was available on whether 40 samples of 5 ears each or 5 samples of 200 ears should be examined, i.e., examination of a large number of small samples or a small number of large samples. What information is needed to make a reliable decision? Those of us involved with the Agricultural Experiment Station regional project concerned with the problems of bird damage to crops, known as NE-49, thought we might supply an ans¬wer if we had a corn field in which all the damage was measured. If all the damage were known, we could then sample this field in various ways and see how the estimates from these samplings compared to the actual damage and pin-point the best and most accurate sampling procedure. Eventually the investigators in four states became involved in this work1 and instead of one field we were able to broaden the geographical base by examining all the corn ears in 2 half-acre sections of fields in each state, 8 sections in all. When the corn had matured well past the dough stage, damage on each corn ear was assessed, without removing the ear from the stalk, by visually estimating the percent of the kernel surface which had been destroyed and rating it in one of 5 damage categories. Measurements (by row-centimeters) of the rows of kernels pecked by birds also were made on selected ears representing all categories and all parts of each field section. These measurements provided conversion factors that, when fed into a computer, were applied to the more than 72,000 visually assessed ears. The machine now had in its memory and could supply on demand a map showing each ear, its location and the intensity of the damage.

Dogs Gone Wild: Feral Dog Damage in the United States

Feral dogs have been documented in all 50 states and estimates of damage in the U.S. from these animals amount to >$620 million annually. In Texas alone, it is estimated that over $5 million in damage to livestock annually can be attributed to feral dogs. We reviewed national statistics on feral dog damage reported to USDA, APHIS, Wildlife Services for a 10-year period from 1997 through 2006. Damage by feral dogs crossed multiple resource categories (e.g., agriculture, natural resources); some examples of damage include killing and affecting the behavior and habitat use of native wildlife; killing and maiming livestock; and their role as disease vectors to wildlife, domestic animals, and humans. We review the role of dog damage in the U.S., synthesize the amount of damage between resource categories (agriculture, human health and safety, disease, and natural resources), and report trends in dog damage during the 10-year period. Results showed an increase in dog damage across all resource categories indicating the importance of management.

Thermal Imagery Applied to Reducing Bird Hazards to Aircraft at Airports

Airports worldwide are at a disadvantage when it comes to being able to spot birds and warn aircrews about the location of flocks either on the ground or close to the airfield. Birds simply cannot be easily seen during the day and are nearly invisible targets for planes at night or during low visibility. Thermal imaging (infrared) devices can be used to allow ground and tower personnel to pinpoint bird locations day or night, thus giving the airport operators the ability to launch countermeasures or simply warn the aircrews. This technology is available now, though it has been predominately isolated to medical and military system modifications. The cost of these devices has dropped significantly in recent years as technology, capability, and availability have continued to increase. Davison Army Airfield (DAAF), which is located about 20 miles south of Ronald Reagan National Airport in Washington, DC, is the transient home to many bird species including an abundance of ducks, seagulls, pigeons, and migrating Canadian geese. Over the past few years, DAAF implemented a variety of measures in an attempt to control the bird hazards on the airfield. Unfortunately, when it came to controlling these birds on or near our runways and aircraft movement areas we were more reactive than proactive. We would do airfield checks several times an hour to detect and deter any birds in these areas. The deterrents used included vehicle/human presence, pyrotechnics, and the periodic use of a trained border collie. At the time, we felt like we were doing all we could to reduce the threat to aircraft and human life. It was not until a near fatal accident in October 1998, when we truly realized how dangerous our operating environment really was to aircraft at or near the airfield. It was at this time, we had a C-12 (twin-engine passenger plane) land on our primary runway at night. The tower cleared the aircraft to land, and upon touchdown to the runway the aircraft collided with a flock of geese. Neither the tower nor the crew of the aircraft saw the geese because they were obscured in the darkness. The end result was 12 dead geese and $374,000 damage to the C-12. Fortunately, there were no human fatalities, but it was painfully clear we needed to improve our method of clearing the runway at night and during low visibility conditions. It was through this realization that we ventured to the U.S. Army Communications and Electronics Command for ideas on ways to deal with our threat. It was through a sub-organization within this command, Night Vision Labs, that we realized the possibilities of modifying thermal imagery and infrared technology to detecting wildlife on airports.

ECOLOGICAL CONTROL OF BIRD HAZARD TO AIRCRAFT

The Canadian Wildlife Service has had twenty-five years experience with the problem caused by bird contacts with aircraft. I experienced my first bird strike, while flying as an observer on a waterfowl survey in August, 1940. Officers of the Service investigated bird problems at airports at Yarmouth, Nova Scotia, and Cartierville, Quebec, in the late 1940's. Those incidents involving gulls and low speed piston-engined aircraft caused minor damage to the aircraft but considerable disturbance to the operators. As aircraft speeds increased and airports became more numerous and busier the problem increased in extent and complexity. By 1960 it was apparent that the problem would grow worse and that work should be directed toward reducing the number of incidents. In 1960 an electra aircraft crashed at Boston, Massachusetts, killing 61 passengers. Starlings were involved in the engine malfunction which preceded the crash. In November, 1962 a viscount aircraft was damaged by collision with two swans between Baltimore and Washington and crashed with a loss of 17 lives. Those incidents focused attention on the bird hazard problem in the United States.