A. Status of the Spectacled Eider - U.S. Fish and Wildlife Service
A. Status of the Spectacled Eider - U.S. Fish and Wildlife Service
A. Status of the Spectacled Eider - U.S. Fish and Wildlife Service
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representative <strong>of</strong> <strong>the</strong> breeding populations as a whole. Surveys should be designed to be<br />
representative <strong>of</strong> <strong>the</strong> breeding populations.<br />
C2.5. 1. Monitor brood production on <strong>the</strong> YKD<br />
C2.5.2. Monitor brood production on <strong>the</strong> NS<br />
C2.5.3. Monitor brood production in AR~<br />
C2.6. Quantify clutch sizes <strong>and</strong> nest <strong>and</strong> egg survival rates. Based on current data <strong>and</strong><br />
preliminary modeling (Appendix III), low production is not suspected to have caused <strong>the</strong><br />
observed population declines. Yet for detailed demographic modeling to be accurate,<br />
annual production data should be ga<strong>the</strong>red in conjunction with duckling <strong>and</strong> adult<br />
survivorship data. At least two study sites should- be sampled for each <strong>of</strong> <strong>the</strong> three<br />
populations. Sampling should include clutch size <strong>and</strong> hatching success. Studies within<br />
each population should be conducted concurrently so that data are statistically comparable.<br />
Identifying <strong>the</strong> proximate causes <strong>of</strong>egg mortality (e.g., infertility, dead embryos,<br />
predation) may illuminate potential obstacles to population recovery. Changes in clutch<br />
size <strong>and</strong> hatching success should be compared among years as well as locations. Some<br />
previous studies may provide data for comparison with on-going studies <strong>and</strong> <strong>the</strong>se data sets<br />
should be evaluated.<br />
C2.6. 1. Monitor nesting success on <strong>the</strong> YKD. Reproductive success data have been<br />
ga<strong>the</strong>red at <strong>the</strong> Hock Slough <strong>and</strong> Kigigak Isl<strong>and</strong> study sites since 1992, providing<br />
preliminary input for modeling. Although a low priority by itself, annual reproductive<br />
success data should continue to be ga<strong>the</strong>red at <strong>the</strong>se sites coincidentally with <strong>the</strong><br />
ongoing survivorship studies (task C2. 1.1), if feasible, so that site-specific population<br />
dynamics can be assessed. Fur<strong>the</strong>r, indications <strong>of</strong> high frequency <strong>of</strong> egg addling rates<br />
on <strong>the</strong> YKD need to be investigated to determine if addling has increased <strong>and</strong> what<br />
effect it may have on total production.<br />
C2.6.2. Monitor nesting success on <strong>the</strong> NS. Comparable data on nesting from both<br />
developed <strong>and</strong> undeveloped sites on <strong>the</strong> NS may be useful for addressing <strong>the</strong> hypo<strong>the</strong>sis<br />
that industrial development has adversely affected local populations. Fur<strong>the</strong>r, this<br />
information is needed to interpret comparisons between NS <strong>and</strong> o<strong>the</strong>r populations.<br />
Current studies within <strong>the</strong> NS oil fields could be duplicated in ecologically similar,<br />
undeveloped sites. Reproductive success data could be obtained coincident with<br />
survivorship studies (task C2. 1.2) or section 7-related evaluations.<br />
C2.6.3. Monitor nesting success in AR<br />
C3. Evaluate <strong>the</strong> impact <strong>of</strong>biological studies on eider hatching success <strong>and</strong> brood survival<br />
Based on studies <strong>of</strong> o<strong>the</strong>r species on <strong>the</strong> YKD <strong>and</strong> incidental observations, researchers have<br />
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