The U.S. Fish and Wildlife Service is looking to establish a control order allowing certain agencies to take without permit nonnative cattle egrets and barn owls in Hawaii, the Northwestern Hawaiian Islands and part of the Midway Atoll.
The proposed rule for a control order is needed to protect threatened and endangered native species such as the endangered Hawaiian petrel, threatened Newell’s shearwaters and the endangered Hawaiian stilt, among others, the service said. Cattle egrets and barn owls, introduced in the 1950s by the then-territorial government’s Hawaii Board of Agriculture and Forestry, pose a serious predation risk and have been documented preying upon native species’ chicks, as well as competing for food native species need to survive.
“Nonnative species in Hawaii displace, compete with, and consume native species, many of which are endangered, threatened, or otherwise in need of additional protection,” a draft environmental assessment that accompanies the proposed rule reads. “Predations by cattle egrets and barn owls is currently having a direct, detrimental impact on numerous threatened or endangered species in the Hawaiian Islands.”
The proposed rule was included in the Nov. 4 Federal Register, a daily publication of the federal government that issues proposed and final administrative regulations of its agencies. A draft National Environmental Policy Act was also released with the proposed rule.
Cattle egrets and barn owls were introduced to deal with pests on farms and ranches, particularly rodents in sugar cane and horn flies on cattle, according to the service.
However, “No measurable decline in rodent or horn fly populations has been associated with cattle egret or barn owl populations,” the draft EA reads.
Both species have expanded in range and population size and now pose a predation problem for various native Hawaiian bird species, including several threatened and endangered species, according to the service.
Cattle egrets, introduced in 1959, are widespread on the major Hawaiian Islands and Northwestern Hawaiian Islands, taking refuge in wetland areas, atolls and open grassland, according to the service.
The egret has been observed to prey on the young of the endangered Hawaiian stilt, Hawaiian coot, Hawaiian common moorhen and Hawaiian duck in both lower and upland areas. It has also been documented on Lanai preying upon the chicks of pueo, or the Hawaiian short-eared owl. The egret also forages on wetland invertebrates, competing with native birds for the food source, according to the service.
Barn owls, introduced in 1958, are found in all habitat types, from the sea to upper elevation forests, of the main Hawaiian Islands. Scientists are concerned the owls will soon establish populations in the Northwestern Hawaiian Islands.
Though considered a rodent specialist throughout continental North America, barn owls in Hawaii have been documented preying upon multiple avian species and may pose a significant threat to nocturnal seabirds such as the Hawaiian petrel and Newell’s shearwaters.
“Loss of adult petrels to owls is significant. Predation on breeding adults leads to reduced breeding success, and owl predation at all life stages prevents successful implementation of planned recovery actions for the species,” the service wrote in the rule proposal.
Control of barn owls and cattle egrets has been attempted using nonlethal methods and site-specific permitted take, without effective results, according to the service. While the taking of the egret and barn owl, including relocation of the birds, has resulted in temporary declines in population, the birds soon recolonize.
“Because nonlethal methods have been unsuccessful in reducing the problems caused by the cattle egrets and barn owls in Hawaii and because these species are nonnative to Hawaii, we are proposing regulations that would allow take by certain authorized agencies,” the service said, adding that introducing predators to the egret and owl would pose a “key threat to native species and habitats.”
Means of take for cattle egrets and barn owls include egg oiling, egg and nest destruction, firearms, trapping, cervical dislocation and carbon dioxide asphyxiation. If euthanasia is required, American Veterinary Medical Association euthanasia guidelines must be followed.
The agencies proposed to conduct control activities are the U.S. Fish and Wildlife Service, U.S. Department of Agriculture, Animal and Plant Health Inspection Service, U.S. Geological Survey, U.S. Department of Defense, National Park Service, Hawaii Department of Land and Natural Resources’ Division of Forestry and Wildlife, Hawaii Department of Agriculture, and the University of Hawaii’s Pacific Cooperative Studies Units which comprises Invasive Species Council staff on each island. Any take must be reported to the Fish and Wildlife Service annually.
The rule does not contain a provision allowing for take of the birds on private property. Permission must be obtained from landowners before conducting any activities authorized by the rule.
It also prohibits the release of sick or injured cattle egrets by wildlife rehabilitators, veterinarians and others.
The proposed rule can be viewed online by visiting regulations.gov and searching for “Docket FWS-HQ-MB-2013-0070.” The draft environmental assessment may also be downloaded via the website.
Comments on the proposed rule are due by Feb. 3. They can be submitted electronically via the website or mailed to Public Comments Processing, Attention: FWS-HQ-MB-2013-0070, Division of Policy and Directives Management, U.S. Fish and Wildlife Service, 4401 North Fairfax Drive, MS 2042-PDM, Arlington, VA, 22203-1610.
Comments on the National Environmental Policy Act required draft environmental assessment should be sent to Migratory Bird Management, U.S. Fish and Wildlife Service, 911 Northeast 11th Ave., Portland, OR, 97232-4181. They can also be emailed to PermitsR1MB@fws.gov.