This study examined the nesting patterns and movements of spectacled eiders on Kigigak Island in Alaska from 1998-2012. The researchers found that: 1) Nest success had a significant effect on dispersal distance between consecutive years, with unsuccessful nests dispersing farther on average than successful nests. 2) There was no significant variation found in average yearly dispersal distances between years. 3) Comparisons to a previous 1992-1997 study found differences in dispersal distances of unsuccessful nests, which the authors attributed to differences in sample sizes, data selection, and analysis methods between the studies.

1. Region NW SW E
NW 78 3(1) 2(1)
SW 5(1) 67 2
E 2 3(2) 27
# moved to 7 6 4
# stayed in 6 3 3
Figure 3: Coded nasal discs and plastic tarsal bands helped facilitate resights with scopes, binoculars
and cameras. If unable to resight visually, mist nets and bow net traps were used.
OBJECTIVES
 Describe the spatial patterns
and movements of nesting
females on Kigigak.
 Examine the relationship
between nest success and nest
dispersal distance in
consecutive years.
 Investigate possible
changes in nest site
fidelity since an initial
assessment was
completed by Tina
Moran in 2000.
Callie B. Moore1, Kyle A.Spragens1,2
1 U.S. Fish & Wildlife Service, Yukon Delta National Wildlife Refuge, Bethel, AK 99559
2 Current: U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, Vallejo, CA 94592
Data Collection
 Resight and nest data from 1998-2012 was used in our analysis.
 We compared our results to data collected between 1992-1997.
 Mean initiation dates and fox index were calculated based on data from
the Yukon-Kuskokwim Delta Waterfowl Nest Plot Reports.
Data Analysis
 Dispersal distance of nest sites of known marked birds observed in two
consecutive years (t vs. t+1) was calculated using nest coordinates in
excel.
 If ≥ one egg hatched in a nest it was deemed successful.
 A one-way ANOVA (α = 0.05) was used to compare the effects of nest
success on dispersal distances in successful and unsuccessful groups.
 Variation in the average dispersal distances between years was also
tested using a one-way ANOVA.
INTRODUCTION
A decline in the North American spectacled eider
(Somateria fischeri) population between 1970
and 1990, prompted the Yukon Delta NWR to
establish a remote field camp on Kigigak Island,
AK in the early 90’s to monitor the population
and assess possible reasons for the decline. To
date 1,933 spectacled eiders have been banded, of which a large
percentage have been resighted and contributed to multiple
nesting attempts. With such a large portion of the female
population being marked (approx. 80.7% of observed nesting
hens in 2011) and the small size of the island (31.8 km2), it is
apparent that the breeding-site fidelity of this population is quite
strong. Multiple encounters of marked individuals at unique
locations have raised questions as to whether fidelity analyses
can be narrowed to a much smaller scale (i.e. region, area, pond).
DISCUSSION
 The complex dynamics of the
island make it difficult to gauge
how much nest success
influences nest dispersal.
To better assess this topic
other factors including; age,
levels of nest success and habitat changes need to be included.
 Individual females varied in their patterns of dispersal (i.e. stayed
in the same region, made multiple region moves, moved to one
region but then returned back to original region (Figure 2).
 Moran’s study did not find a significant difference between groups,
while ours did. Although our analysis were similar they were not
identical which makes comparing the results difficult. We believe
that this was the result of; differences in sample size (5 yrs vs. 14
years of data), data selection criteria, and analysis methods.
RESULTS
 Analysis of average yearly
dispersal rates between years
resulted in no significant
variation.
 Nest fate in year t had a
significant effect of on the nest
dispersal distance in year t+1 at
the p<0.05 level for the two
conditions (F1,307 = 21.6,
P = 4.9E-06).
 Dispersal averages of
unsuccessful birds varied
greatly between the two studies
(Figure 4).
CONSIDERATIONS
 An in depth investigation of this long-term dataset is necessary to
determine all the factors influencing breeding ecology and to
produce proper population estimates for the recovery team.
 Assessing the influence of the populations limited dispersal on
genetic diversity would be worthwhile.
 Understanding the factors that drive spectacled eider nest
selection is vital to our knowledge of all eider breeding ecology, as
results could inform essential biological decisions across all
species. For example, the initiation of the threatened Steller’s
eider reintroduction project on Kigigak (summer 2016).
ACKNOWLEDGEMENTS
Funding provided by YDNWR and MBM. Thank you to all the technicians and biologists
who devoted countless hours to data collection on Kigigak over the past 24 years. Lew
Coggins, Wildlife Biologist YDNWR, for his data analysis expertise, and to all the staff
at the YDNWR for their comments and support on this project.
Figure 4: Mean dispersal distance of successful
and unsuccessful groups between studies (1998-
2012 &1992-1997) with error bars depicting their
95% CI.
302
792
100
200
300
400
500
600
700
800
900
1000
1100
1200
AverageDispersal(m)
Successful
Unsuccessful
(n=270)
(n=39)
Q.1.12
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-10 -8 -6 -4 -2 0 2 4 6 8 10
AnnualDiff.toMeanFoxPressureIndex
Annual Diff. to Mean Nest Initiation Date
2004
2014
HIGH PRESSURE
LOW PRESSURE
2002
2005
2007
2008
2009 20132010
2011
2003
2006
2001
1998
1999
2000
2012
Figure 2: Spatial patterns of marked females from 1998-2012 in relation to nest success. Green dots
represent successful nests, while red dots depict unsuccessful.
Figure 5 (above): The level of
yearly burden that two primary
pressures (nest initiation date
and fox pressure) had on YKD
waterfowl nest success
Table 1 (left): Summary of
regional nesting movements on
Kigigak Island ‘98-’12. Diagonal
shows # of females found in
each nesting region and never
migrate from that region.
to
from
 Evaluate possible drivers of nest dispersal and relationships (i.e.
Nest initiation dates, fox pressure, spatially-biased competition).
METHODS
Figure 1: Kigigak Island located
on the western coastal zone of
Yukon Delta NWR, near the
mouth of Baird Inlet.