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

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A final consideration involves information related to, but not specifically addressed in, the criteria listed above. One of the purposes ofthe Endangered Species Act is to “provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved.” The Service has recently instituted an ecosystem approach to fish and wildlife management. As part ofthis effort, the Service has defined 52 ecosystems nationwide. The YKD is one of7 terrestrial ecosystems in Alaska, and the NS comprises a major portion ofthe Arctic Alaska ecosystem. Thus, from an ecosystem perspective, the two Alaskan populations of Spectacled Eiders inhabit different ecological settings. Element m - Status Ifa population segment is discrete and significant (i.e., it is a distinct population segment), its evaluation for endangered or threatened status will be based on the Act’s definition ofthose terms and a review ofthe factors enumerated in section 4(a). It may be appropriate to assign different classifications to different distinct population segments ofthe same vertebrate taxon. Analysis The three Spectacled Eider populations warrant designation as distinct population segments. All three fulfill at least one criterion under both the discreteness and significance elements ofthe vertebrate population policy. This recovery plan calls for analysis ofthe status ofeach Spectacled Eider population in respect to the recovery criteria outlined in the next section (Part II- Recovery). The status and trend of the YKD population are well known; only recently have minimum population estimates been obtained for AR and NS populations. The YKD population is quite low relative to historical levels and has sustained a steep, long-term population decline. The AR population is quite large, but no reliable trend information is likely to be available in the near future. Survey data over 3 years suggest that the NS population is larger than originally suspected (Dau and Kistchinski 1977), and continued annual surveys should provide trend data within a few years. Status reviews ofAR and YKD populations appear warranted at this time. Additional years ofsurvey data are required for the NS population before a status review is appropriate. 28
II. RECOVERY A. Objective and Criteria Overview The objective of this plan is to provide strategies that recover the world population of Spectacled Eiders so that the species can be delisted. Criteria and threshold levels for reclassifying. (i.e., from threatened to endangered or from endangered to threatened) and for - complete delisting are presented in the following discussion. Justification for the use of specific thresholds appears in Appendices I and II. The Service will obtain recommendations for reclassification and delisting from the Spectacled Eider Recovery Team, or, if the Recovery Team no longer exists, by independent review of the evidence by qualified scientists. For reclassifying the status of Spectacled Eiders, the status of each of the 3 major populations will be considered independently. Unless otherwise indicated, the term “population” means thepool ofbirds that breeds in one ofthree primary geographic areas (YKD, NS, and AR; see Section E, Introduction). A few tens of Spectacled Eiders also may nest on St. Lawrence Island and the Seward Peninsula of Alaska. For the purposes of this plan, they will be classified with the NS population until data are obtained that support an alternative approach. The goal of classifying populations as threatened or endangered is to establish priorities for research and management according to the relative risk the populations face. One widely used measure of risk is the probability of becoming extinct in a specified amount of time. The probability of going extinct cannot be measured directly; it can, however, be estimated as the consequence of the population growth rate and the variability in that rate. For Spectacled Eiders, we must convert abundance estimates through time (i.e., trends) into measures ofrisk (e.g., probabilities ofextinction). Uncertainty in Decision-making Translating trend data into measures of risk is not a straightforward task. Because we cannot count all the birds in a population, measures ofabundance are uncertain. In addition, population growth rates may be relatively constant through time or they may fluctuate widely. This uncertainty makes our decisions about classifying a population according to risk uncertain as well. Appendices I and II address this complexity and describe in detail how population growth rate, estimated by regressing abundance against time, is translated into risk of extinction. The implications ofuncertainty are provided here in a less technical format. 29
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 36 and 37: E. Distinct Population Segments The
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
Page 86 and 87: ___________ 1967. The geese of the
Page 88 and 89:
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
Page 104 and 105:
TASK PRIOR- Dj ITYU — — A12.3 2
Page 106 and 107:
— TASK U — 135.2 PRIOR- TASK DE
Page 108 and 109:
TASK U PRIOR- ITY U TASK DESCRIPTIO
Page 110 and 111:
TASK PRIOR. U — DS.3 3 TASK DESCR
Page 112 and 113:
The final risk factor is the effect
Page 114 and 115:
This PVA will treat two population
Page 116 and 117:
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
Page 134 and 135:
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
Page 148 and 149:
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
Page 156 and 157:
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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