1. Population Delineation and Sea Ducks presented to SDJV Continental Technical Team at November 2015 meeting John Pearce, USGS Alaska Science Center

2. Population Delineation
This talk came about because:
I questioned how the SDJV was defining “population delineation” at the last meeting
I want the SDJV to more visible in how it is completing this work and be clear about what we are funding
Population delineation is important, but often difficult to express and quantify

3. Population Delineation
From the 2015 SDJV Implementation Plan:
“Lack of understanding about delineation is one of the highest priorities for future work” AGREE
The primary method for “tracking sea ducks is satellite telemetry” DISAGREE, on two counts
Tracking sea ducks ≠ pop. delineation
Primary methods for pop. delineation

4. No overlap of band recoveries from Alaska and
Barrow’s Goldeneye
No overlap of band recoveries from Alaska and
Western North America
Alaska
Western North America
> 400 winter recoveries

5. Sampling areas are significantly differentiated
Barrow’s Goldeneye
Quebec
British Columbia, Idaho
Iceland
Alaska
Sampling areas are significantly differentiated

6. Population Delineation
From the 2015 SDJV Implementation Plan:
Telemetry also yields data on “seasonal habitat use and site fidelity, thus informing conservation” ???
Highest priority for is to “complete population delineation” for BLSC, SUSC, WWSC and LTDU NEED TO CLARIFY

7. Population Delineation
Poorly studied but needed:
Savard et al. (2015) mentioned delineation as a gap in 6 of 15 chapters:
Harvest
Conservation
Population dynamics
Status and trends
Migration
Conclusions and future directions

8. Dan Esler Presentation: Summary of 1,547 publications on sea ducks
SDJV Era (1999 to 2011)
Pre-SDJV (≤ 1998)
Percent of papers
Productivity
Dispersal
Survival
Population
Delineation
Population
Dynamics
Population
Models
Demographic studies have seen large proportional increases during
SDJV era.

9. Population Delineation
Complicated with highly migratory species
We need to define what type of delineation scenario exists for each species or region
Will help to show how we have completed this task for different species and regions

10. Long-tailed duck Sea duck population delineation scenarios
Breeding Area 1
Breeding Area 2
Winter Area 1
Winter Area 2
Breeding Area 1
Breeding Area 2
Winter Area 1
Winter Area 2
Long-tailed duck
Breeding Area 1
Breeding Area 1
Breeding Area 2
Winter Area 1
Winter Area 2
Winter Area 1

11. Population Delineation
I’m not proposing redefining “population delineation”
But we need some way to “complete” the population delineation work and categorize each species or region
What does a “complete” picture look like? Full coverages of N. America? Only priority species?

12. Population Delineation
SDJV supported science should be testing hypotheses about delineation rather than portraying migratory routes
This may involve multiple methods
Ask ourselves: Are PTT studies funded by the SDJV “completing population delineation” for priority species and regions?

13. Are we after (a) or (b)?

14. Population Delineation
Stop focusing on fidelity:
It is a cool behavior, but misleading
But not a measure of demographic independence unless we know where the bird originally came from
Only a measure for delineation if fidelity = philopatry or if fidelity is 1.0 and migratory connectivity is high (one breeding area to one wintering area)

15. Estimating fidelity (F)
Burnham models
Marked
Alive
Survival (S)
Recapture (p)
Alive
(recaptured)
Alive
(not recaptured)
Fidelity (F)
Alive
(recaptured)
Dead
Recovery (r)

16. Dau et al. (2000)
Hypothesized that because of high molt site fidelity of Steller’s Eiders to specific beaches, that birds molting in specific locations could be from unique breeding areas (molting populations would represent unique sub-populations).
However, band recoveries suggest that eiders molting in a specific location likely represent birds from multiple breeding areas. Conclude no sub-population structuring for Steller’s eiders molting along the Alaska Peninsula.

17. Hooded Mergansers Capture (p = 0.62) Survival (S = 0.72)
Site fidelity
Capture (p = 0.62)
Survival (S = 0.72)
Fidelity (F = 0.92)

18. Genetic methods
Hooded Merganser

19. Genetic methods Arrows indicate significant differentiation
mtDNA (n = 134)
ΦST = 0.05
6 nuclear loci (n = 213)
Hooded Merganser
FST = 0.01
= DNA samples
Arrows indicate significant differentiation
Site fidelity based on band recovery appears inconsistent with DNA information

20. Comparison between endemic cavity nesting species
mtDNA (n = 134)
ΦST = 0.05
Hooded Merganser
Gene flow or recent divergence?
mtDNA (n = 44)
ΦST = 0.31
Wood Duck
(Peters et al. 2005)

21. “Isolation with Migration” (IM)
Gene flow or recent divergence?
Time since divergence ( ≥ 10,000 y)
Migration
1.4
Hooded Merganser
3.8
1.1
0.07
Wood Duck
(Peters et al. 2005)
“Isolation with Migration” (IM)

22. Hooded Mergansers
Breeding site fidelity is not a universal proxy for population structure and in the case of this species, fidelity does not equal philopatry
Juvenile dispersal
Adult emigration

23. “Evidence for significant structuring”
Population delineation via mtDNA
Not different
Very different
“Evidence for significant structuring”
(J. Avise 2000)
0.01
0.20
0.50
0.70
FST among populations

24. Site fidelity, dispersal, and impact of future change
Hooded merganser
Common Goldeneye
Barrow’s Goldeneye
Bufflehead
Common merganser
0.01
0.20
0.70
Fidelity
68%
92%
91%
63%

25. Site fidelity, dispersal, and impact of future change
Hooded merganser
Common Goldeneye
Barrow’s Goldeneye
Bufflehead
Common merganser
0.01
0.20
0.70
Fidelity
68%
92%
91%
63%
Dispersal
High
High
Intermediate
Low
Impacts?
Low
Low
Intermediate
High

26. Definitions of “fidelity” in the Atlantic and Great Lakes Sea Duck Migration Study 2014 Progress Report
Species
Sex
Status
Type of fidelity
Number returns
Percentage
Distance between used sites (km)
Surf Scoter F
Breeding
“Strong”
2 of 23 8%
0.5
Black Scoter
“Exhibits fidelity”
12 of 12 in consecutive years
100%
3.25 (but one at 63 not included) M
Molt
“High”
6 of 15
40%
Not given
Winter
Not stated 84
White-winged Scoter
“Quite high”
12 of 18
<50
Long-tailed Duck 5

27. Population Delineation
Recommendations:
Complete (?) the picture (?)
Target populations that are of management concern?
Declining breeding populations. How many wintering areas? Is the issue on the breeding or wintering area?
Harvest of winter populations (one or several breeding populations?)
Calculate fidelity with caution