A. Status of the Spectacled Eider - U.S. Fish and Wildlife Service

decline over a several-year period, in conjunction with a specific minimum population size, or
a low minimum size of the breeding population signifies the possibility of imminent extinction
of that population. The =5samples (surveys) should be taken over =5consecutive years,
although the use of consecutive years is not a formal requirement. Use of trend data is also
limited to the 15 most recent years to omit historical data from current estimates of risk.
Further, the specified rate of decline does not have to be met every year of the sampling
period--it only must average this rate over the entire sampling period.
Criteria for Reclassifying from Endangered to Threatened
A population will be considered for reclassification from endangered to threatened status when
the five factors for listing under the Endangered Species Act are reviewed for evidence of
threats to the population and when:
(1) The population is increasing asjudged by the following statistical measures:
- the over-protection loss exceeds the under-protection loss, which is
calculated using trend data [basedon at least 10 years (1 survey/year) of
data but not exceeding a 15 year period] and where loss functions are
symmetrical around r = 0 with a zero loss for both functions when r = 0
(see Appendix II, Figure Il-i); AND
- the minimum estimated population size is =3,000breeding pairs for =1
year;
(2) The minimum estimated population size is =5,000breeding pairs over =3surveys (1
OR
survey/year, with surveys preferably being consecutive).
Note that the criteria for reclassifying from endangered to threatened status are independent, in
that either criterion may be met for reclassification to occur. Before reclassifying a population
from endangered to threatened, however, there should be high confidence that the population~
is increasing and that it has increased in overall size to the point at which it is no longer in
imminent danger of extinction. Knowing the exact rate of increase of the population is not a
formal requirement in this case--there simply should be strong evidence that an increase is
occurring. If, however, the population meets criterion (1) above within 10 years, it will have
increased dramatically from endangered levels. It is more likely that the population will
increase at a slower rate, requiring more than 10 years for the minimum estimated population
size of3,000 breeding pairs to be achieved. This increased time, in turn, will increase the
statistical power of the test and, thus, confidence that the population actually is increasing.
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