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

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E. Distinct Population Segments The Endangered Species Act (as amended in 1978) provides protection to “...any distinct population segment ofany species ofvertebrate fish or wildlife which interbreeds when mature.” Congress (Senate Report 151, 96th Congress, 1st Session) instructed the Secretary ofthe Interior to exercise this authority “...sparingly and only when the biological evidence indicates that such action is warranted.” In the “Policy Regarding the Recognition ofDistinct Vertebrate Population Segments under the Endangered Species Act” (USFWS 1996), the Service defined “distinct population segment” forthe purposes oflisting, delisting and reclassif~,’ing vertebrates. Under the policy, three elements are to be considered sequentially in determining the status ofa potentially distinct population segment: 1) the discreteness ofthe population relative to the rest ofthe species; 2) the significance ofthe population segment to the species; and 3) the population segment’s conservation status in relation to the Act’s standards for listing (i.e., is the population segment endangered or threatened when treated as ifit were a species?). The three breeding populations ofSpectacled Eiders (i.e., YKD, NS, and AR) meet the criteria for designation as distinct population segments under the policy. The criteria for evaluating each element are presented below, along with the corresponding analyses ofthe Spectacled Eider breeding populations. Element I - Discreteness Criteria A population segment ofa vertebrate species may be considered discrete ifit satisfies one ofthe following criteria: 1. It is markedly separated from other populations ofthe same taxon as a consequence of physical, physiological, ecological, or behavioral factors. 2. It is delimited by international governmental boundaries within which differences in control ofexploitation, management ofhabitat, conservation status, or regulatory mechanisms exist that are significant in light ofsection 4(a)( 1 )(D) ofthe Act. Analysis The three main breeding populations are physically separated from one another by several hundred kilometers, and, on that basis alone, they fulfill the first criterion ofbeing “markedly separated.” Although perhaps only reflecting facultative responses to the environment, these populations also exhibit marked ecological and behavioral differences such as different migration routes and breeding chronologies. No data exist to evaluate the possibility ofphysiological differences. 26
Under this policy, Spectacled Eiders breeding in Russia and Alaska can be defined as separate populations as well, because ofthe international boundary separating their nesting grounds. Although this criterion is not based in biology, it clearly reflects Congress’ intent to recognize populations which might be negatively affected by international inconsistencies in conservation policy. Element II- Significance Criteria If a population segment satisfies at least one ofthe above criteria for discreteness, its biological and ecological significance will then be considered. This consideration may include, but is not limited to, the following: 1. Persistence ofthe discrete population segment in an ecological setting unusual or unique for the taxon. 2. Evidence that the loss ofthe discrete population segment would result in a significant gap in the range ofthe taxon. 3. Evidence that the discrete population segment represents the only surviving natural occurrence ofa taxon that may be more abundant as an introduced population outside its historic range. 4. Evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics. Because precise circumstances are likely to vary considerably from case-to-case, it is not possible to describe prospectively all the classes ofinformation that might bear on the biological and ecological importance ofa discrete population segment. Analysis The first two significance criteria are germane to the Spectacled Eider populations in question. Under the first criterion, the YKD population is unique in two ways: it is the only major subarctic population and the only population limited almost exclusively to vegetated intertidal habitats. On both counts, the YKD population warrants designation as a significant population segment. All three populations warrant distinct population status under the second criterion, for the loss ofany one ofthe three would result in a significant gap in the range ofthe taxon. The third criterion does not apply to the Spectacled Eider. The possibility ofgenetic differentiation among the three populations (criterion 4) is currently being explored, but the analysis has not yet been completed. 27
Page 2 and 3: SPECTACLED EIDER RECOVERY PLAN Team
Page 4 and 5: LITERATURE CITATION U.S. Fish and W
Page 6 and 7: EXECUTIVE SUMMARY OF THE RECOVERY P
Page 8 and 9: TABLE OF CONTENTS DISCLAIMER PAGE 1
Page 10 and 11: LIST OF FIGURES Figure 1. Breeding
Page 12 and 13: A. Status of the Spectacled Eider R
Page 14 and 15: ) a) j~ 25000 0 2 220000 C ~15000 ~
Page 16 and 17: B. Causes for Decline and Obstacles
Page 18 and 19: Increasing interest in avicultural
Page 20 and 21: Other conservation measures include
Page 22 and 23: D. Natural History of the Spectacle
Page 24 and 25: Figure 4. Yukon-Kuskokwim Delta loc
Page 26 and 27: DEL?A RUSSIA SPECTACLED EIDER RANGE
Page 28 and 29: helicopter surveys in the Prudhoe B
Page 30 and 31: geographic populations, because imm
Page 32 and 33: Figure 8. Study sites and land stat
Page 34 and 35: their diseases (e.g., Schiller 1954
Page 38 and 39: A final consideration involves info
Page 40 and 41: Trend data are analyzed to inform w
Page 42 and 43: Figure 10. A hypothetical posterior
Page 44 and 45: thresholds are not “magic numbers
Page 46 and 47: Criteria for Reclassifying from Thr
Page 48 and 49: Criteria for Delisting from Threate
Page 50 and 51: The final aspect ofSpectacled Eider
Page 52 and 53: concordance in their descriptions o
Page 54 and 55: data on both levels and effects oft
Page 56 and 57: implicated. In the absence of histo
Page 58 and 59: . - currently small size of the YKD
Page 60 and 61: implementation of the Memoranda ofA
Page 62 and 63: . take of Spectacled Eiders. In add
Page 64 and 65: . AlS. Produce a handbook summarizi
Page 66 and 67: . Bl.4. 1.3. Develop visibility cor
Page 68 and 69: B2. 1.1. Implement YKD satellite tr
Page 70 and 71: . Appendix Ill). Since epidermal ag
Page 72 and 73: . feasible if post-fledging staging
Page 74 and 75: presumed that their activities have
Page 76 and 77: contaminants within Spectacled Eide
Page 78 and 79: limited ability to withstand additi
Page 80 and 81: surface after a year and is no long
Page 82 and 83: . The reproductive stages (eggs, yo
Page 84 and 85: is inadequate to sustain “normal
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___________ 1967. The geese of the
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Dementev, G.P., and N.A. Gladkov (e
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___________ 1 964a. Observations on
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Nelson, E.W: 1887. Report upon natu
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________ P.R. Wade, R.A. Stehn, and
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Robert M. Platte, Migratory Bird Ma
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KEY Task Duration and Costs TBD - T
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TASK 324.2 I 12.4.1 .2 PRIOR- — 2
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TASK I — [37 E12 EI.3 fTYU —PRI
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TASK PRIOR- Dj ITYU — — A12.3 2
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— TASK U — 135.2 PRIOR- TASK DE
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TASK U PRIOR- ITY U TASK DESCRIPTIO
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TASK PRIOR. U — DS.3 3 TASK DESCR
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The final risk factor is the effect
Page 114 and 115:
This PVA will treat two population
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Both aerial surveys are conducted a
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0.2 0.15 -j i 4 0.1 0 -I 0.05 0.08
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emaining before the population reac
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) critical population size; and (2)
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40%. The population growth rate cri
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Table 1-2. Results of simulation wh
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Hilborn, R. and C.J. Walters. 1992.
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APPENDIX II TECHNICAL DETAILS OF TH
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The likelihood function for the par
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initial sample. Then the O~ were re
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LU ~0.8 z -J ~0.6 I-ET1 w107 480 m1
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LITERATURE CITED APPENDIX LI De la
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where x = age. The fertility rate i
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of older females: (1) older females
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RESULTS Solutions for single cause
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0.1 0.08 ~0.06 4 0 0.04 0. 0.02 0 0
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growth rate. Perhaps this can be mo
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decline, by far the fastest way to
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LITERATURE CITED APPENDIX In Bailli
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APPENDIX IV SPECTACLED EIDER RECOVE
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APPENDIX V COMMENTS RECEIVED ON DRA
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A. Status of the Spectacled Eider - U.S. Fish and Wildlife Service

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