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Home Land Upland Species and Communities

Peregrine Falcon

Status and Trend

Interpretation and Commentary

PEREGRINE FALCON


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Status: At or Somewhat Better Than Target
Trend: Moderate Improvement
Confidence: Moderate

 

  • Relevance - Peregrine Falcon (Falco peregrinus anatum) populations declined precipitously across the country in the mid-1900s (USFWS 2003). They were recorded in the Tahoe Basin in the early 1900s (Orr and Moffitt 1971), but were not observed naturally occurring in Tahoe between 1960 and 2007 (Romsos et al. 2000; S. Zanetti personal communication, August 15, 2011; DFG 2007). In the mid-1980s, several juveniles were re-introduced, but left the Tahoe Basin the same year (USDA 2009e). The species was considered endangered under the federal Endangered Species Act until they were removed from endangered status in 1999 due to an overall increase in the population. They were, however, considered endangered by the State of California until 2009. Their recovery is a result of banning DDT and similar chemical contaminants, and active re-introductions (USFWS 2003). They are still protected by the Migratory Bird Treaty Act, which prevents harming Peregrine Falcons or their nests.
  • Adopted Standards  - Provide a minimum of 2 population sites (defined as active nests) and a 0.25 mile non-disturbance zone around population sites.
  • Indicator - The number of active Peregrine Falcon nests detected each year.
  • Status – Previous habitat evaluations concluded that the Tahoe Basin contains less than ideal nesting habitat (Boyce and White 1980), and prior reintroduction efforts were not successful (USDA 2009e). As a result, Peregrine Falcons were not expected to nest in Tahoe and nest surveys were only conducted sporadically. In 2007, several biologists reported seeing Peregrine Falcons in Tahoe, and the U.S. Forest Service began conducting annual nest surveys in 2008. In 2011, two active nests were confirmed and indications of one additional nest was observed, but not confirmed. The Threshold Standard of two population sites is in attainment. Two mapped areas have been identified by TRPA for the protection of Peregrine Falcon population (see map below).
  • Trend –  There is an apparent increasing trend in the number of active nests, based on available data from the seven formal surveys that have been conducted over the past 18 years. The trend is consistent with an increase in Peregrine Falcon abundance nationally (USFWS 2003) and across California (Linthicum 2006).

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  • Confidence  - There is a high degree of confidence in the presence of all confirmed active nests because they are positively identified by qualified biologists. However, confidence is low in the trend due to the limited survey effort prior to 2008. The overall confidence in the status and trend is medium.
  • Human and Environmental Drivers - In some areas Peregrine Falcons have shown reduced reproductive success when nesting cliffs are used by rock climbers (Mearns and Newton 1988; Cade et al.1996). In Tahoe, some of the cliffs containing nests are used by rock climbers (USDA 2009e), which could affect nesting success. An evaluation of potential Peregrine Falcon habitat in Tahoe concluded that potential nesting habitat exists, but it is of marginal quality, which may limit the total number of active nests the region can support (Boyce and White 1980). Some Peregrine Falcons nesting in Tahoe may migrate to Central or South America for the winter, where they could be affected bycontamination from organochlorine pesticides (e.g. DDT) (USFWS 2003).
  • Monitoring Approach – Biologists observe historic or potential nest sites for a minimum of 4 hours per month, April–August following standard U.S. Forest Service protocol. Incidental sightings are used the help focus surveys on likely nest locations.
  • Monitoring Partners – U.S. Forest Service

Links

 
  • Monitoring Plan
  • Conceptual Model

Map

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Areas identified by TRPA for the protection of Peregrine Falcon nesting habitat in the Tahoe Basin.

 

Trend Charts

Chart data not available at this time.
 

Additional Info

References

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Additional Information

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  3. Conceptual Model:
  4. Monitoring Plan:
Last Updated on Friday, 31 August 2012 10:50