Bird Damage Unit Records --

National Wildlife Research Center (NWRC) scientists have conducted research on a broad range of bird species and problems over the years. Research began when C. Hart Merriam founded the predecessor of the Wildlife Services program within the USDA in 1885. Researchers in the Economic Ornithology and Mammalolgy Division collected data on the geographic distribution of various birds and mammals in the U.S. and used this information to educate farmers about the birds and mammals that affected their agricultural interests. In 1905, the name was changed to the Bureau of Biological Survey (BBS), and in 1914, the BBS began collaborating with Land Grant Universities around the country, greatly expanding their scope of research.

In the 1920s and 1930s, bird unit research focused on avian disease, control of birds in urban environments, and feeding and nesting habits. The development and use of certain warfare chemicals during World War I carried over into animal control practices after the war, as researchers increasingly experimented with chemical control methods. During the 1920s, the headquarters of the BBS Control Methods Research Laboratory was moved to Denver, Colorado, where investigations of wildlife diseases such as avian botulism were initiated. In the 1930s, the BBS established a Division of Food Habits in Denver. In 1939, the BBS was transferred to the U.S. Fish and Wildlife Service (USFWS). The Division of Food Habits joined the Control Methods Laboratory to become the Denver Wildlife Research Laboratory in 1940.

During the food shortages of the World War II years, minimal food crops could be lost to agricultural pests. To aid the war effort, the Denver Research Laboratory worked directly with the Office of Scientific Research and Development on new chemicals to control birds, rodents, and predators threating vital wartime food supplies. Many chemicals could not be imported during the war, so several new and promising areas of investigation were studied and developed. Much of the research during this time focused on the food habits and impacts of major agricultural bird pests, primarily blackbirds and crows. Many bird-banding studies were initiated in the 1940s as well.

In the post-World War II era of the 1950s and 1960s, wildlife research efforts expanded as both bird and human populations increased. Much effort continued to be directed at identifying effective chemical methods to protect key food crops such as grains (rice, corn, and sunflower) and fruits (grapes, cherries, and blueberries) from bird depredations and to reduce large roosting congregations of blackbirds, particularly in the southern U.S. Chemical repellents such as Avitrol, wetting agents like PA-14 and CPT, and avicides such as DRC-1339 and Mesurol were the central focus of many bird studies during this time. Research to protect feedlots from bird depredation and disease was also initiated. Laboratory and field testing of DRC-736 began in 1961, with tests conducted at feedlots north of Denver, Colorado.

In 1959, the name of the Denver Wildlife Research Laboratory was changed to the Denver Wildlife Research Center (DWRC). From the 1960s through the 1980s, DWRC researchers conducted numerous field studies at Sand Lake National Wildlife Refuge in South Dakota. Researchers at Sand Lake investigated several methods to protect cornfields from blackbird damage. Research included bird banding studies, mass-marking techniques, food habit studies, and field trials of chemical frightening agents.

An upsurge in the use of aircraft following World War II opened the door to another area of bird research. Bird hazards to aircraft became a prominent issue after a Lockheed Electra crashed in Boston Harbor, Massachusetts, in 1960. Bird-induced crashes in the 1970s at Atlanta, Georgia, and at JFK International Airport in New York led to DWRC efforts to comply with FAA regulations that airports manage bird hazards through habitat management and control techniques.

As the U.S. established itself as a world leader during the Cold War era of the 1960s and 1970s, the DWRC began a long-term international research program in collaboration with the U.S. Agency for International Development (USAID). Researchers focused on discovering, developing and applying new and better methods to protect world food crops from rats, bats, and birds. DWRC scientists investigated ways to reduce bird damage to rice crops in Haiti and wheat crops in Bangladesh. As well, radio telemetry studies on Quelea were initiated to protect ripening grain in Africa. DWRC scientists continued to work in Africa, Asia, the Caribbean, and Latin America well into the 1990s.

By the 1970s, public and Congressional concerns over chemical pollutants in the environment led to a ban on many of the chemical agents utilized by the DWRC. As a result, agency scientists began to focus more studies on developing non-toxic control methods. Environmental concerns also led to the passage of the Endangered Species Act in 1973. Consequently, the USFWS began to commit more resources to conservation management, and the DWRC increasingly conducted research on newly-listed endangered species.

Beginning in 1979, the DWRC and the Biologically Active Natural Products Laboratory of the USDA collaborated to determine the repellency of a number of insect repellents to wild birds. Dozens of repellents were tested for acute repellency and toxicity to blackbirds. Research projects on blackbird and starling movements were also conducted in Arkansas, Kentucky, and Tennessee from 1977 to 1981. To track bird movements and roosting populations at winter roost sites, miniature radio transmitters were attached to birds' tails. Additionally, researchers used a paint-tagging method to gather data on migration patterns and roosting habits.

In the 1980s, DWRC and University scientists continued to collaborate on developing methods to protect the corn, sunflower, rice, fruit, and feedlot industries from blackbird and starling damage. Studies to improve repellents, develop bird-resistant hybrids, conduct taste-aversion tests, advance alternate-cropping practices, and cultivate lure-cropping strategies were conducted during this period. DWRC scientists also evaluated nonlethal repellents and harassment and dispersal techniques such as kite-hawk models, balloons, human effigies, lasers, Mylar reflecting tape, and distress calls. Songbirds became a subject of much research in the 1970s and 1980s as well. Studies on American robins, house finches, and cedar waxwings focused on the birds’ impact on fruit crops like grapes, cherries, and blueberries.

In 1986, bird damage problems, along with mammal and predator control, were transferred to the Animal and Plant Health Inspection Service (APHIS). DWRC researchers evaluated the use of DRC-1339-treated rice baits and aerially-applied avicides to reduce bird damage to rice crops. Studies also evaluated surfactants such as CPT and PA-14 for reducing large roosting congregations of blackbirds, grackles, and starlings. This research all but died out during the early 1990s, mainly due to environmental concerns and registration difficulties.

Involvement in aquaculture research began in earnest during the late 1980s when the DWRC established a field station in Starkville, Mississippi. Here, scientists investigated the impacts of fish-eating birds on aquaculture in the mid-South and methods to manage these impacts. Efforts initially focused on double-crested cormorants, but subsequently expanded to include herons, egrets, and pelicans.

During the 1990s, the name of the DWRC was changed to the National Wildlife Research Center (NWRC) to acknowledge the scope of the agency’s efforts. Bird strike hazards, aquaculture, and endangered species, as well as waterfowl, gulls, and cormorants were subjects of increased research during this time. Bird strike hazard research focused on developing non-lethal methods such as habitat management techniques and strategies compatible with on-site endangered species management. Studies on waterfowl and gulls involved nuisance problems, aircraft hazards, fish depredations, and human health and safety. Investigations associated with wading birds and cormorants included aquaculture, commercial and sport fisheries, and transmission of fish diseases. Waterfowl research at this time was related to Canada geese, repellents, egg oiling, habitat studies, and reducing depredations to southern aquaculture farms.

Bird studies on the impacts of blackbirds, starlings, and grackles to agricultural crops in the 1990s were replaced by research related to crows, ravens, vultures, and pelicans in the early 2000s. Environmental studies at this time included developing methods to protect endangered species such as the California least tern from predation by ravens, and to reduce hazards associated with environmental contaminants.

As human-bird conflicts evolved throughout the twentieth century, so too did the research of scientists in the NWRC’s Bird Unit. From food habit studies, to chemical control research, to bird strike hazards, to endangered species protection, to aquaculture, to non-lethal control methods, researchers at the NWRC have consistently conducted the necessary research to meet the changing needs of bird damage control.