BLACKBIRDS AND CORN IN OHIO

Damage to corn by blackbirds (Icteridae) has been an economic problem throughout historical times in North America. Ohio, with the highest nesting season population density of red-winged blackbirds (Agelaius phoeniceus) in North America and large acreages of corn, has been a key State in this conflict. Surveys of damage from 1968 to 1979 revealed that blackbirds annually destroyed less than 1% of the corn crops in Ohio, a 4- to 6-million dollar loss at 1979 prices. This total dollar loss is somewhat misleading because of the uneven distribution of damage among fields. Over 97% of the cornfields in Ohio receive less than 5% loss and these losses make up about 60% of the total loss in the State. Damage control efforts need to be primarily directed toward the remaining 3% of the fields that often incur losses greater than 5% and constitute about 40% of the total loss in the State. Most of these fields are located within 8 km (5 miles) of the marshes containing concentrations of roosting birds in late summer. Successful programs to reduce damage must use one or more of a series of management measures, integrated with normal farming practices. The selection of management measures should be based on assessments of amount and type of bird damage likely to occur in a field and constraints imposed by farming practices. Management recommendations include (1) planting of hybrids with ear tips well covered by husks; (2) reduction of weed and insect populations to make the field less attractive to birds; (3) judicious use of mechanical frightening devices or a chemical frightening agent at the time birds initially damage the maturing corn; (4) the provision of natural or planted food and cover sites outside the corn; and (5) harvesting the crop, especially sweet corn, as early as possible

Bird and Other Wildlife Hazards at Airports: Liability Issues for Airport Managers

Aircraft collisions with birds (bird strikes) and other wildlife are a serious economic and safety problem. The problem has increased in the past decade because of expanding populations of many wildlife species that are hazardous to aviation (Dolbeer and Eschenfelder 2002). Cleary et al. (2004) estimated wildlife strikes (98% involving birds) cost the civil aviation industry in the USA about $500 million/year, 1990-2003. Allan and Orosz (2001) estimated that bird strikes annually cost commercial air carriers over$1.2 billion worldwide, 1999-2000. At least 194 people died and 164 aircraft were destroyed as a result of bird and other wildlife strikes with civil and military aircraft from 1988-2004 (Richardson and West 2000, Thorpe 2003, Cleary et al. 2004, Dolbeer unpublished data)

Increasing Trend of Damaging Bird Strikes with Aircraft Outside the Airport Boundary: Implications for Mitigation Measures

A basic tenet of programs to mitigate the risks of bird strikes with aircraft has been to focus management efforts at airports because various historical analyses of bird-strike data for civil aviation have indicated the majority of strikes occur in this environment during take-off and landing at (AGL). However, a trend analysis of birdstrike data involving commercial air carriers from the U.S. National Wildlife Strike Database for Civil Aviation, 1990 to 2009, indicates that this tenet should be revised. The percentage of all strikes that occurred at \u3e500 feet AGL increased significantly from about 25% in 1990 to 30% in 2009. The percentage of all damaging strikes that occurred at \u3e500 feet increased at a greater rate, from about 37% in the early 1990s to 45% during 2005 to 2009. I also examined trends in strike rates (strikes/1 million commercial aircraft movements) for strikes occurring at \u3c and \u3e500 feet. From 1990 to 2009, the damaging strike rate at \u3e500 feet increased from about 2.5 to 4.0, whereas the damaging strike rate for strikes at (Branta canadensis), the most frequently struck bird species with a body mass \u3e1.8 kg, showed a pattern similar to that for all species. I conclude that mitigation efforts incrementally implemented at airports in the United States during the past 20 years have resulted in a reduction of damaging strikes in the airport environment. This reduction in strikes has occurred in spite of increases in populations of Canada geese and many other species hazardous to aircraft. However, these successful mitigation efforts, which must be sustained, have done little to reduce strikes outside the airport. Increased efforts now are needed to eliminate bird attractants within 5 miles of airports, to further develop bird-detecting radar and bird-migration forecasting, and to research avian sensory perception to enhance aircraft detection and avoidance by birds

REPRODUCTION IN THE RED SQUIRREL (TAMIASCIURUS HUDSONICUS) IN COLORADO

Information on reproduction of the red squirrel (Tamiasciumrs hudsonicus) can be gleaned from studies in the northeastern United States (Klugh, 1927; Hamilton, 1939; Layne, 1954) and in western Canada (Miller, 1970; Smith, 1968; Kemp and Keith, 1971; Wood, 1967). However, there is a paucity of information on reproduction from the mountainous regions of the western United States. This paper presents reproductive information on the red squirrel from Colorado and helps fill this void. In addition, the reproductive strategy of red squirrels is briefly compared with that of snowshoe hares

MIGRATION PATTERNS OF DOUBLE-CRESTED CORMORANTS EAST OF THE ROCKY MOUNTAINS

The 5589 recovery records for Double-crested Cormorants (Phalacrocorax auritus) banded in North America from 1923 to 1988 were analyzed to determine migration patterns and the source of populations wintering in the lower Mississippi Valley and Gulf of Mexico coastal region. Autumn migration from areas north of latitude 42°N primarily occurred in October and November. Spring migration occurred mainly in April for birds \u3e2 yr old and in May for birds \u3c1 yr old. During summer,1-yr-old birds were recovered significantly farther from their natal colony than were older birds. Cormorants nesting in Canada and the northern United States from Alberta to the Gulf of St. Lawrence migrated in winter primarily to the southern United States between Texas and Florida. There was considerable mixing and overlap in winter of nesting populations from widely divergent areas. From 38 to 70% of the birds from Saskatchewan throughout the Great Lakes region were recovered in the lower Mississippi Valley as were 10% of the birds from such disparate areas as Alberta and the New England coast. There was little mixing of populations from east and west of the Rocky Mountains

Aerodrome Bird Hazard Prevention: Case Study At John F. Kennedy International Airport

The collision of birds with aircraft is a serious problem at John F. Kennedy International Airport (JFKIA), New York. Gulls (Larus spp.) accounted for 86% of bird strikes (an aircraft striking \u3e1 bird) from 1988-1990, averaging 260 strikes/year. Laughing Gulls (L. atricilla) are present from May- September in association with a protected nesting colony in Jamaica Bay National Wildlife Refuge adjacent to the airport. The colony increased from 15 nests in 1979 to 7,629 nests in 1990. During the 1970s and 1980s, JFKIA implemented various management activities to reduce gull strikes, including maintenance of tall grass, improved sanitation, drainage of standing water, and increased harassment. These programs, although beneficial as part of an integrated bird management program, did not result in reduced numbers of gull strikes. A specific program to reduce gull strikes was undertaken from May-August 1991-1998 in which 2-5 people stationed on airport boundaries shot gulls flying over the airport. In 7,159 person-hours of shooting, 55,452 gulls were killed (2,263-14,866/year), comprised of 50,521 Laughing Gulls and 4,931 other gulls (L. argentatus, L. marinus, L. delawarensis). The number of aircraft striking gulls declined to a mean of 68.4/year in 1991-1995, a 74% reduction compared with the mean of 259.7 strikes/year for 1988-1990. As a result of the shooting program, the overall bird strike rate declined at JFKIA but the proportion of strikes caused by non-gull species increased, from 14% in 1988-1990 to 39% in 1991-1995. To further reduce strikes by gulls and other species and to minimize the need to shoot gulls, JFKIA implemented an experimental falconry program in 1996-1998. Falconry has provided positive publicity for JFKIA and additional personnel on the airport to disperse birds. However, a statistical analysis of strike data did not indicate falconry reduced the strike rate below levels achieved during the shooting program in 1991-1995. In 1996-1998, when shooting and falconry were both active, the mean gull strike rate (57.3/ year) was similar to the rate recorded in 1991-1995 (68.4/year). Strikes by non-gull species increased in 1996-1998 ( = 85.3/year) compared to 1991- 1995 (43.0/year). Non-gulls comprised 60% of all bird strikes, 1996-1998. The number of gulls killed/person-hour of shooting was highest in 1991- 1992, the first 2 years of the shooting program, but did not differ (P \u3e 0.05) among years from 1993-1998. JFKIA, located in a bird-rich coastal environment, has developed innovative programs to reduce strikes by various bird species whose dynamic populations present ever-changing challenges. A new component of these integrated programs should be the relocation of the nearby gull nesting colony to a site away from JFKIA

WINTER BEHAVIOR OF THE EASTERN BOX TURTLE, TERRAPENE C. CAROLINA L., IN EASTERN TENNESSEE

A field study of winter movements and depths and types of hibernacula of the eastern box turtle, Terrapene carolina carolina L., was undertaken from October 1968-January 1969

Population Increases of Large Birds in North America Pose Challenges for Aviation Safety

There is a strong correlation between bird mass and the likelihood of aircraft damage during a bird–aircraft collision. Thus, the U.S. Federal Aviation Administration (FAA) has established airworthiness standards related to bird mass for engines, airframes, and windshields. Most standards use large (1.8 kg) and medium (1.1 kg) birds as benchmarks (the empennage and certain large turbofan engines use a 3.6-kg bird). There are 20 large (≥1.8 kg) and 16 medium (1.1–1.7 kg) bird species in North America with ≥20 strikes reported for civil aircraft (FAA National Wildlife Strike Database), 1990 to 2018. I analyzed the population changes of these 36 species from 1990 to 2018 in relation to flocking behavior. For the 20 large species, the combined population had a net gain of 27.8 million birds (129% increase). For the 16 medium species, the combined population had a net gain of 6.7 million birds (20% increase). Notably, all 9 species with body mass ≥3.6 kg indicated population increases. In agreement with the increased numbers of birds, the number of strikes involving large and medium birds showed significant (P \u3c 0.01) positive trends from 1990 to 2020 as did strikes involving multiple birds. The threat to aviation safety from large and medium birds, especially flocking species, was much higher in 2018 than in 1990. Although progress is being made to mitigate the risk by management programs to keep large and medium birds away from airport properties, these actions do little to mitigate the threat during climb and approach phases of flight. Enhanced airworthiness standards for aircraft components, bird-detecting radar to provide real-time warnings, and aircraft lighting schemes to improve visibility of aircraft to birds are priority areas of research and development to mitigate these off-airport threats to aviation safety

Have Population Increases of Large Birds Outpaced Airworthiness Standards for Civil Aircraft?

Bird-aircraft collisions (bird strikes) are an increasing safety and economic concern to the USA civil aviation industry, costing over $400 million each year. One approach to reducing risks associated with strikes is to require commercial aircraft components to meet certain standards of safe performance in the event of a bird strike. The Federal Aviation Administration has developed airworthiness standards for airframes, windshields and engines using a single 4-lb (1.82-kg) bird mass as the maximum that must be tested (with the exception of a single 8-lb bird for the empennage, 6-lb bird for certain mid-sized engines that may be developed in the future, and an 8-lb bird for certain large-intake engines on aircraft such as the Boeing 777). Because of concern within the aviation industry that populations of certain flocking bird species weighing more than 4 lbs, such as Canada geese (Branta canadensis), have increased dramatically, discussions are underway in the USA and Europe regarding the need to revise 4- and 8-lb test standards to heavier body masses or to include multiple strikes. To help clarify this issue, we surveyed the avian literature and determined that 36 and 14 of the approximately 650 bud species that nest in North America (north of Mexico) have average body masses (for at least 1 gender) greater than 4 and 8 lbs, respectively. Of the 31 species for which population trend data were available, 24 (77%) showed population increases over the past 2040 years, 2 showed declines, and the other 5 were stable. Thirteen of the 14 species with mean body masses over 8 lbs showed population increases. At least 261 strikes with \u3e4-lb birds caused substantial damage to civil aircraft in the US4 1990-2001. Furthermore, multiple buds were involved in 31% of the strikes with \u3e4-lb buds and 40% of the strikes with \u3e8-lb buds. Therefore, we conclude that airframe, windshield, and engine standards, as well as proposals to allow high-speed (\u3e250 knot) operations below 10,000 feet, should be reevaluated to address the threat posed by increased populations of large flocking buds. Finally, because most critical aircraft components are not designed to withstand strikes by birds greater than 4 lhs, wildlife biologists who work at airports should increase efforts to detect, remove and disperse these large buds from airport environments