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Recovery | Stories | Frequently Asked Questions Regarding the Peregrine Falcon Monitoring Plan
Photo credit: USFWS
Why is a monitoring plan necessary?
The Endangered Species Act (ESA) requires the Fish and Wildlife Service to monitor species recovered and removed from the endangered species list "...in cooperation with States..." and "...for not less than five years." In order to fulfill this requirement, the Service developed this plan in cooperation with State resource agencies, representatives from each Fish and Wildlife Service Region, the Divisions of Migratory Birds, Endangered Species, and other cooperators.
Who wrote the plan?
A team of Fish and Wildlife Service employees from each of the Service’s regions, plus a National Coordinator from our Pacific Northwest region wrote the monitoring plan. They are listed in Appendix A of the plan. The members brought to the team different levels of experience with peregrines, bird biology, and designing population monitoring programs. The team benefitted from the advice of a few members with many years of experience monitoring peregrines, and from outside review by biologists in other Federal agencies, State agencies, and other interested parties
How did the peregrine falcon get its name?
This plan has been under development since the species was delisted in 1999. Although other species have recovered, and been delisted, and monitored, this is the first monitoring plan to be written for such a wide-ranging species (nesting in 40 States). In addition, midway through the planning process, responsibility for writing and implementing the monitoring plan shifted within the Service from the Division of Endangered Species to Migratory Birds and State Programs. Migratory Birds and State Programs oversees the conservation of birds protected by the Migratory Bird Treaty Act. Thus, a combination of administrative and biological challenges, plus opening several comment periods and the large number of commenters, delayed publication of the plan. Meanwhile, the Service has continued to collect data from State programs and other organizations monitoring peregrines since 1999, and those data show that the peregrine population continues to grow. In addition, a pilot program began in 2002; full implementation began this year.
How will the American peregrine falcon be monitored?
Biologists will visit previously occupied territories of nesting pairs of American peregrine falcons at least two times during the breeding season. First, observers will determine whether or not the territory is occupied, then they will return later in the nesting season to determine whether or not territories occupied by pairs of birds also have nests that are successful, i.e. have young older than 28 days of age. At that point, the monitors will count the young they see as a measure of productivity.
Who will do the monitoring?
Many Federal and State resource agencies, non-governmental organizations, and volunteers have been closely monitoring peregrines during their recovery, from the 1970s to the present. The Service will be supporting these existing monitoring efforts, and helping to establish new monitoring programs wherever necessary, to fulfill the requirements of the monitoring plan.
Why did the Service choose to monitor American peregrines falcons 5 times at 3-year intervals?
The Monitoring Team chose to monitor Peregrines five times at three-year intervals, beginning in 2003 and ending in 2015 (i.e., sampling will occur in 2003, 2006, 2009, 2012, and 2015). Five monitoring periods meets the requirement of ESA (to monitor "...for not less than five years..."); the three-year interval spreads the monitoring over 13 years, reflecting our concern for the long-term rather than short-term future of the Peregrine.
The Peregrine population currently is secure; the population continues to increase as it has for 30 years. The Monitoring Team believes this trend will continue at least over the short-term. The long-term future is less certain; although the threat to Peregrines from some contaminants has been controlled, we believe that contaminants still pose the most likely future threat to Peregrine populations: they have a demonstrated vulnerability to contaminants, exposure to contaminants still occurs, and future compounds might pose a risk to Peregrines. Population-level effects from contaminants are likely to take place over a relatively long- rather than short-term. Monitoring every year over the long-term would be excessive, unnecessary in the face of increasing population trends, and costly. In the end, monitoring 5 times at 3 year intervals over 13 years will provide sufficient comparative data and trend information on territory occupancy, nest success and productivity to measure effects from what we believe to be the most likely potential threats to Peregrines, contaminants.
Why is the Service monitoring contaminants if DDT is banned?
Peregrines, as predators, remain vulnerable to persistent environmental contaminants. Although contaminants played a large role in the decline of peregrines, there has been no systematic nationwide effort to monitor exposure of these birds (or other similarly-affected species) to chemical threats. Research over the past 20 years in Alaska suggests that mercury is currently at levels in peregrines that can affect reproduction, and may be increasing over time. In the Big Bend area of Texas, mercury, selenium and perhaps DDE may be contributing to low productivity of peregrines. The continual introduction of anthropogenic chemicals to the environment far outpaces research on their effects on wildlife. Considering the peregrine’s history with contaminants, and the potential for future contaminant threats, the monitoring team decided to include in the plan requirements for collecting addled eggs (eggs that failed to hatch), and snippets of feather tips from nestlings for analysis, to monitor loads of past, current, or emerging contaminants that may pose a threat to peregrines.
Will the Service be able to detect potential effects of West Nile Virus?
The monitoring plan is designed to detect declines in regional peregrine populations that might arise from a variety of threats, including West Nile Virus. First documented in the United States in 1999 in northeastern States, West Nile Virus spread rapidly. As of August 20, 2003, it was reported in all but 2 of the contiguous United States (NV and OR). Birds are a reservoir for the virus and mosquitoes are the vector between birds, horses, and people. As of August 2003, 163 species of birds have been found to be at least somewhat susceptible to the virus. The list includes several species of hawks, including American kestrel (Falco sparverius), merlin (Falco columbarius), and prairie falcon (Falco mexicanus) which are closely related to peregrines. In September of 2002, a moribund 2-year old peregrine was picked up in New Jersey; it died two weeks later. Extensive tests showed definite exposure to, and probable death from, West Nile Virus. In July 2003, evidence emerged from one nest in Virginia that three of four peregrine nestlings might have succumbed to West Nile Virus; the fourth nestling and one moribund adult were rehabilitated, and tests are underway to evaluate whether or not they had been exposed. These cases suggest that peregrines are also succeptible; however, species apparently vary in their abilities to develop immunity to the disease. The falconry community is alert to the possibility of infection from the virus, and will be quick to report deaths of peregrines from this disease should they be found. The Service, State agency biologists, and cooperators are also asked to report birds found dead, and to submit them for analysis using protocols suggested by State and local health departments (see links at the Centers for Disease Control West Nile virus page and also the USGS West Nile virus map page.
The Service will depend on its extensive network of contacts with other government officials, State wildlife agencies, and other cooperators to detect and report cases of WNV in peregrines. If peregrines are found to be susceptible to WNV to the point of threatening falcon populations, the Service will work with other agencies to attempt to stabilize populations, as well as initiate a review to determine what measures might be taken to curb this threat and whether or not to relist the species under ESA § 4(b)(7).
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