TECHNICAL REPORT BREEDING ECOLOGY OF STELLER’S AND SPECTACLED EIDERS NESTING NEAR UTQIAĠVIK, ALASKA, 2016-2017 Prepared by: Nathan Graff Endangered Species Branch Fairbanks Fish and Wildlife Field Office 101 12th Ave., Room 110 Fairbanks, Alaska 99701 Fish and Wildlife Service U.S. Department of the Interior February 2018 Disclaimer: The mention of trade names or commercial products does not constitute endorsement or recommendation for use by the Federal Government. This report may be cited as follows: Graff, N. R. 2018. Breeding ecology of Steller’s and spectacled eiders nesting near Utqiaġvik, Alaska, 2016-2017. U. S. Fish and Wildlife Service, Fairbanks Fish and Wildlife Field Office, Fairbanks, Alaska. Technical Report. 46 pp. TABLE OF CONTENTS TABLES ........................................................................................................................................ iii FIGURES ....................................................................................................................................... iv ACKNOWLEDGMENTS ...............................................................................................................v INTRODUCTION ...........................................................................................................................1 Background ..........................................................................................................................1 Objectives ............................................................................................................................4 METHODS ......................................................................................................................................6 Abundance and Distribution Surveys ..................................................................................6 Road-based survey. ..................................................................................................6 Ground-based breeding pair survey .........................................................................6 Aerial survey ............................................................................................................9 Chronology…… ................................................................................................................10 Nest Searching and Monitoring .........................................................................................10 Nest searching ........................................................................................................10 Nest monitoring .....................................................................................................12 Nest cameras ..........................................................................................................12 Habitat Use…….................................................................................................................13 Hen Capture.... ...................................................................................................................13 Statistical Analyses. ...........................................................................................................14 Clutch size and nesting chronology .......................................................................14 Nest survival ..........................................................................................................14 RESULTS ......................................................................................................................................15 Abundance and Distribution Surveys ................................................................................15 Road-based survey .................................................................................................15 Ground-based breeding pair survey .......................................................................16 Aerial survey ..........................................................................................................16 Chronology ........................................................................................................................18 Temperature, precipitation, and snow melt ............................................................18 Nest initiation and hatch dates ...............................................................................20 Nest Searching and Monitoring .........................................................................................20 Nest searching ........................................................................................................20 Nest monitoring .....................................................................................................21 Steller's eiders ...........................................................................................21 Spectacled eiders .......................................................................................22 Nest cameras ..........................................................................................................22 Nest predators ............................................................................................22 Incubation behavior ...................................................................................23 i Habitat Use.........................................................................................................................23 Ground-based breeding pair survey .......................................................................23 Nests ....................................................................................................................24 Hen Capture .......................................................................................................................25 Nest captures ..........................................................................................................25 Steller's eiders ............................................................................................25 Spectacled eiders ........................................................................................26 Other sea ducks ..........................................................................................26 DISCUSSION ................................................................................................................................26 LITERATURE CITED ..................................................................................................................30 APPENDIX A. Observations of Steller’s and spectacled eider adults and extent of annual survey area from the ground-based breeding pair surveys near Utqiaġvik, Alaska 2016-2017……………………………………………...……………………….34 APPENDIX B. Ground-based pair survey results for all species counted near Utqiaġvik, Alaska 2016-2017. ...........................................................................................................36 APPENDIX C. Steller’s and spectacled eider nests found near Utqiaġvik, Alaska 2016-2017...37 APPENDIX D. Egg fates for Steller’s eider nests in 2016-2017 near Utqiaġvik, Alaska ...........39 APPENDIX E. Steller’s eider nest survival near Utqiaġvik, 1991-2017 .....................................40 APPENDIX F. Nesting by Steller’s eiders and avian predators near Utqiaġvik, 1991-2017 .......41 APPENDIX G. Steller’s eider breeding biology study, 1991-2017: a brief review .....................42 APPENDIX H. Reports of the Steller’s eider breeding biology study for 1991-2017 .................46 ii TABLES Table 1. Behavior codes for avian species counted during the breeding pair survey area near Utqiaġvik, Alaska. .............................................................................................................8 Table 2. Wetland habitat types used to categorize Steller’s and spectacled eider observations. Roman numerals correspond to wetland classifications described by Bergman et al. (1977) ................................................................................................................................9 Table 3. Counts of Steller’s and spectacled eiders from the annual ground-based breeding pair survey near Utqiaġvik, Alaska, 2016-2017 .....................................................................16 Table 4. Steller’s eider males, nests, and pair densities recorded during ground-based and aerial surveys conducted near Utqiaġvik, Alaska 1999-2017 ...................................................17 Table 5. Mean monthly temperature and total precipitation at the NOAA weather station in Utqiaġvik, Alaska 2016-2017. Shaded columns are temperature and un-shaded are precipitation. ....................................................................................................................19 Table 6. Average daily high temperatures in Utqiaġvik for the month of June and during the ground-based breeding pair survey period, 1999-2017 ...................................................19 Table 7. Mean nest initiation and hatch dates for Steller’s and spectacled eiders near Utqiaġvik, Alaska 2016-2017. Numbers in parentheses are standard errors. ..................................20 Table 8. Waterfowl nests found near Utqiaġvik, Alaska 2016-2017 ............................................21 Table 9. Average effective clutch size of Steller’s and spectacled eider nests found near Utqiaġvik, Alaska 2016-2017. Numbers in parentheses are standard errors. ................21 Table 10. Habitat use by Steller’s eiders during ground-based breeding