* *

Literature review and summary of
research priorities for Harlequin Duck

A Report to:

ASARCO, Incorporated

Box 868
Troy, MT 59935

Submitted by
JAMES D. REICHEL

May 1996

Montana Natural Heritage Program
1515 East Sixth Avenue

P.O Box 201800
Helena, MT 59620-1800

Oi. ain««i

ixva

© 1996 Montana Natural Heritage Program

This document should be cited as follows:

Reichel, J.D. 1996. Literature review and summary of research priories for Harlequin Ducks. Montana Natural Heritage
Program. Helena, MT. 37 pp.

TABLE OF CONTENTS

INTRODUCTION 1

METHODS AND MATERIALS 2

DISTRIBUTION 2

NORTH AMERICA 2

Breeding range 2

Winter range 3

OUTSIDE THE AMERICAS 3

HISTORICAL CHANGES 3

MOVEMENT '. 4

ON THE BREEDING GROUNDS 4

MIGRATION 5

Nature of the migration in the species 5

Timing and routes of migration 5

Migratory behavior 6

HABITAT PARAMETERS 6

BREEDING RANGE: TERRESTRIAL 6

Overstory 7

Bank composition 7

BREEDING RANGE: AQUATIC 7

Stream width 7

Stream gradient 8

Channel morphology 8

Aquatic habitat 8

Substrate 9

Loafing sites 9

Quality 9

Quantity 9

Food availability 9

Other 10

WINTER (NON-BREEDING) RANGE 10

BREEDING 10

PHENOLOGY 10

Pair formation 10

Nest building 10

Egg laying 10

in

Hatching 10

Postbreeding 10

NEST SITE 10

EGGS 11

INCUBATION 12

DEMOGRAPHY AND POPULATIONS 12

MEASURES OF BREEDING ACTIVITY 12

Age at first breeding; intervals between breeding 12

Clutch size 12

Annual and lifetime reproductive success 13

Proportion of total females that rear at least one brood to nest-leaving 13

Sex ratio , 13

LIFE SPAN AND SURVIVORSHIP 13

CAUSES OF MORTALITY 14

Causes of death 14

Exposure and predation 14

RANGE 15

Dispersal fi"om natal stream 15

Fidehty to natal stream 15

POPULATION STATUS 15

Estimates or counts of density 15

Numbers 16

Trends 16

POPULATION REGULATION 17

CONSERVATION AND MANAGEMENT 17

EFFECTS OF HUMAN ACTIVITY TO HARLEQUIN DUCK POPULATIONS,

REPRODUCTION, AND BEHAVIOR 17

Disturbance on the breeding grounds 17

Noise 19

Collecting and trapping 19

Shooting 19

Fishing 19

Pesticide and other contaminants/toxics 19

Degradation of habitat: breeding and wintering 20

MANAGEMENT 20

Federal 20

States/Heritage Programs 20

Other legal status 21

Mitigation procedures 21

ONGOING RESEARCH THAT RELATES TO ANY OF THE TOPICS LISTED ABOVE 21

IV

PRIORITffiS FOR FUTURE RESEARCH 22

RESEARCH PROPOSALS TO ADDRESS THE MOST CRITICAL DATA GAPS 24

ACKNOWLEDGMENTS 25

REFERENCES 25

INTRODUCTION

The Harlequin Duck {Histhonicus histrionicus) is a small sea duck, which travels inland to
breed on fresh water streams. Harlequins breed in western North America from Alaska and the
Yukon south through western Montana to California (Harlequin Duck Working Group 1993); in
eastern North America, they breed from Baffm Island south to eastern Quebec and Labrador
(Goudie 1993). In the Palaearctic, they breed in Iceland, Greenland and Siberia (A.O.U. 1983).
Approximately 1 10-150 pairs of Harlequins currently breed in Montana (Reichel and Genter
1994), with most located in the following areas: 1) tributaries of the lower Clark Fork River; 2)
tributaries of the North, Middle, and South Forks of the Flathead River; 3) streams coming off the
east front of the Rocky Mountains; and 4) the Boulder River (Miller 1988, 1989, Kerr 1989,
Carlson 1990, Fairman and Miller 1990, Diamond and Finnegan 1992, 1993).

During the breeding season. Harlequins are found along fast mountain streams (Bengtson
1966). In many areas. Harlequins use streams with dense timber or shrubs on the banks (Cassirer
and Groves 1990), but they are also found in relatively open streams along the east slopes of the
Rocky Mountains, Montana (Markum and Genter 1990, Diamond and Finnegan 1992), and the
Arctic tundra (Bengtson 1972). In Idaho, 90% of observations occurred near old growth or
mature timber stands (Cassirer and Groves 1990). Mid-stream rocks, logs, islands, or stream-side
gravel bars serve as safe loafing sites and appear to be important habitat components.

Most of the ducks arrive on their inland breeding areas in mid- April to early-May; unmated
males typically arrive before pairs (Kuchel 1977). The males return to the coast shortly after the
females begin incubation; most are gone by early July (Kuchel 1977). The females and young
remain on the streams until August or early September. This chronology is influenced by
elevation and by the timing of spring runoff; it may vary up to several weeks between years.

The U.S. Forest Service, Region 1, lists the Harlequin Duck as Sensitive (Reel et al 1989).
The species is listed as a Species of Special Concern by the Montana (Montana Natural Heritage
Program 1994) and Idaho (Idaho Conservation Data Center 1994) Natural Heritage Programs.
The eastern North American population is listed as Endangered in Canada (Goudie 1993); the
eastern and western populations are both listed under Category 2 as candidates for protection
under the Endangered Species Act by the U.S. Fish and Wildlife Service (U.S. Department of
Interior 1991).

The Montana Natural Heritage Program began surveying Harlequin Ducks in 1988. The
survey data gave rise to questions involving site fidelity, productivity and mortality. We began
individually marking Harlequins to a limited extent in 1991; through 1995, a total of 249
Harlequins were marked on 9 streams, representing the largest population of marked Harlequins
from breeding streams. Birds marked in Montana have subsequently been captured and observed
on the coasts of Oregon, Washington and British Columbia, with most reports coming from
Vancouver Island. During that time, we observed 20 previously marked adults returning to
Montana streams.

METHODS AND MATERIALS

All literature and reports in the Bibliography section were reviewed and evaluated. Contacts were
made with members of Harlequin Duck Working Group and other knowledgeable individuals to
determine current research projects and their applicability to sections in this report.

DISTRIBUTION

NORTH AMERICA

Breeding range Figure 1,2,3. Breeds in two disjunct regions in North America. The
Pacific population breeds from western Alaska, northern Yukon, northern British Columbia, and
southern Alberta south to Oregon, Idaho, Wyoming, and east of the Continental Divide in
Montana. The Atlantic population breeds from Baffm Island (at least formerly) through central
and eastern Quebec, eastern Labrador, and northern Newfoundland. Occurs in summer in
Mackenzie Valley and near Great Slave Lake, Northwest Territories (Amencan Ornithologists
Union 1983, Harlequin Duck Working Group 1993, 1994).

In the Rocky Mountains of the United States, Harlequins currently breed in western Montana
(Reichel and Center 1995), northern and southeastern Idaho (Cassirer and Groves 1994), and
northwestern Wyoming (Wallen 1993, McEneaney 1994). Distribution within the area is shown
in Figure 2. While much of Montana and Idaho has been surveyed (Figure 3), some areas with
potential habitat have yet to be completed; surveying m Wyoming is less complete. As of 1995,
surveys have been conducted on approximately 5,640 km of streams (Montana - 2,963 km, Idaho
- 1,886 km; Wyoming 792 km) (Cassirer et al. 1996). Using habitat characteristics, accessibility,
amount of human use, and nearby Harlequin Duck occurrences, streams were identified that had
the highest potential for Harlequin Duck occurrence, for which no ducks had been observed; these
included 31 in Montana, 16 in Idaho, and 41 in Wyoming (Cassirer et al. 1996).

In the literature and in unpublished reports. Harlequins within a geographical area often listed
as "breeding on XX number of streams." This has been used differently by various authors to
mean: 1) every named stream, 2) larger named streams; and 3) the major stream in an occupied
drainage. Recently, biologists in Montana, Idaho, and Wyoming have written and adopted the
standard Heritage Program definition of an "element occurrence (EO):" A drainage/portion of a
drainage used by Harlequins where breeding is known or highly suspected (3 or more independent
observations of females or pairs). The EO contains contiguous stream reaches used (and portions
of lakes, reservoirs or bays, if regularly used) during the courtship, nesting, and brood-rearing
periods, and not separated by more than 10 km of unsuitable habitat or 20 km of unoccupied
habitat.

The breeding status on many streams with Harlequin Duck sightings has not been established
in the Rocky Mountains of Montana, Idaho, and Wyoming. In Montana, there are currently 33
Harlequin Duck EOs and 32 streams where Harlequin Ducks have been observed or reported but
on which the breeding status is unknown; these streams have been surveyed 0-5 times each
(Cassirer et al. 1996). In Idaho, there are currently 16 Harlequin Duck EOs and 24 streams
where Harlequin Ducks have been observed or reported but on which the breeding status is
unknown; these streams have been surveyed 0-5 times each (Cassirer et al. 1996). In Wyoming,
there are currently 8 Harlequin Duck EOs and 1 7 streams where Harlequin Ducks have been

observed or reported but on which the breeding status is unknown; these streams have been
surveyed 0-5 times each (Cassirer et al. 1996).

Winter range Winters in the Aleutian and Pribilof islands south on the west coast of North
America to Oregon, rarely to central California; southern Labrador, Newfoundland, Nova Scotia,
south to Maryland (but mostly north of Cape Cod); accidental in Hawaii and the Great Lakes;
much more abundant in the Aleutians than farther south in southwestern Canada and the U.S.
Pacific Northwest (Figures 1).

OUTSIDE THE AMERICAS

Figure 4. In the Palearctic, the Harlequin Duck breeds in Iceland and Greenland in the Atlantic
Ocean, and from the Lena River in Siberia east to Kamchatka and south to northern Mongolia,
the Kurile Islands, and nothern Japan in the Pacific Ocean; winters in Eurasia south from the pack
ice to the east coast of Korea and central Japan in the Pacific and on the Atlantic in the ice-free
zones around Iceland and Greenland (Philips 1925, Salomonsen 1950, Dement'ev and Galdkov
1967, Portenko 1981, American Ornithologists Union 1983, Boertmann 1994).

HISTORICAL CHANGES

The range of the Harlequin Duck has contracted in the past 100 years at both large and small
scales. Historically, Harlequins bred in Colorado, probably as a small isolated population, until at
least 1 883 (Parkes and Nelson 1 976), currently, they do not breed in the state. In Oregon,
Harlequins historically bred in the Wallowa and probably Blue Mountains of the northeastern part
of the state (Gabrielson and Jewett 1940, Latta 1993). They are thought to have historically bred
much more widely in the North Atlantic region (Merriam 1883, Peters and Burleigh 1951, Goudie
1989, 1993).

On a smaller scale, heavy white-water rafting is believed to have been the primary factor in the
displacement and resulting extirpation of Harlequins on the Methow River in Washington (Brady
pers. comm. in Clarkson 1994). In Yoho National Park, Alberta, Harlequins regularly bred in the
vicinity of Lake Ohara until 1985; they have not been seen since then (Hunt and Clarkson 1993).
This area now has heavy recreational use, building facilities, and a hiking trail circling the lake.

Within the Rocky Mountains of Montana, Idaho, and Wyoming, few historic records exist for
either known current or extirpated Harlequin occurrences (Table 1 ). The scant existing evidence
indicates that Harlequin Ducks were once more widespread than they are currently. In addition to
the historic Montana, Idaho, and Wyoming streams listed in Table 1, Harlequins have not been
observed during recent surveys of Big Creek, Quartz Creek, and Trout Creek, indicating that they
may be extirpated fi^om those streams (Table 2).

Table 1. U.S.A. Rocky Mountain streams previously used by Harlequin Ducks where no
use has been documented since 1988 (Cassirer et al. 1996.)

State

Historical consistent use
documented

Historical occasional

breeding

documented

Historical occasional pair
use documented

Idaho

Montana

Wyoming

Kelly Creek and N. Fork
Clearwater River below Kelly
Creek (3)'

Kootenai Falls area of
Kootenai River (11)'

Smith Creek
(Kootenai River)
(3)'

Otatso Creek

Orogrande Creek (N.
Fork Clearwater River)

Bighorn River Canyon
Jocko River
Sweet Water Creek

Shell Creek Canyon

Number in parentheses represents the number of surveys between 1 989 - 1 994

Table 2. Streams in Montana where Harlequins have not been observed during recent
surveys. ^=^^^^^^^^=^=^=^^^^^^==^^^^^==^^^^^==

Stream

Last year seen

Years surveyed since last seen

Big Creek (Kootenai R.)

1990

1991, 93, 94, 95

Quartz Creek (Kootenai R.)

1988

1989,90,95

Trout Creek (Superior)

1990

1991, 92, 93, 95

MOVEMENT

ON THE BREEDING GROUNDS

There is little published literature regarding movement within the breeding grounds. Kuchel
(197.7) found that pairs used lower McDonald Creek prior to establishing home ranges higher in
the stream. Once established, pairs rarely moved more than 1-2 km, although movements of up to
8 km were recorded. Kuchel (1977) found unpaired males moved considerably more, with
movements of up to 10 km found. In a reanalysis of Kuchel's (1977) data, Cassirer and Groves
(1992) found that linear home ranges averaged 7.7 km (5D = 2.34) on McDonald Creek, similar
to the 7 km reaches used in Idaho.

On the Bow River in Banff National Park, 5 pairs of birds were marked at what is probably a
staging area or local migratory corridor (Smith 1996). Two pairs remained in a 2 km section of
river where they were banded and another remained in a 2 km stretch about 12 km downstream;
one pair remained within about 6 km until the female moved about 8 km up a drainage, perhaps to
breed; the final pair moved about 15 km downstream within 22 days (Smith 1996).

In Montana and Idaho, several relatively long-distance movements in the past several years
have been documented both within and between years (Table 3). The movement by the female
and fledged brood to the Vermilion River was likely the result of disturbance due to marking
(Reichel and Center 1996). The female in Glacier Park has been seen at several locations over the
4 years since her banding (Ashley 1995); the locations in Table 3 are the furthest distance apart.

For 35 marked Harlequins, Bengtson (1972) found no movement overland between breeding
streams and movement of only a few km within drainages. Not only did the birds return to the
same drainage, but in 22 out of 33 cases, the birds were observed within 100 m of their locations
during the previous year (Bengtson 1972).

Table 3. Significant movements of Harlequins within and between years on the breeding
grounds (Cassirer and Groves 1994, Reichel and Center 1994, 1996; Ashley 1995, Cassirer
pers. comm.).

Sex and age

1st
Date

Location

2nd
Date

Location

Km
moved

Adult Female

755-76007

Adult Female
& 6 young

755-76013;
925-09336, 37,
38. 39. 40. 41

Adult Male

755-76075

Adult Female

755-76025

8/4/92 Marten Creek, mouth
of (w/ brood)

7/28/95 Marten Creek, near
mouth of

7/30/93 Swamp Creek, T25N
R31W Section 9 (w/
brood)

7/29/95 Vermilion River

5/26/93 Marten Creek, Devils 4/27/95 Vermilion River, 0. 1
Gap mi above Miners

Gulch

8/10/92 McDonald Creek 6/29/95 Middle Fork Flathead

above McDonald Lake River (w/ brood)

(w/ brood)

16

26

31

18

Aduh Female 5/85 Hughes Fork

II 1 7/9 1 Upper Priest River

MIGRATION

Nature of the migration in the species. All inland populations of the species migrate to
coastal waters, A marked female seen on Granite Creek, Idaho on 17 July 1991 was relocated 13
days later off of Battleship Island in the San Juan Islands, Washington (Cassirer and Groves
1992). In Iceland, birds are thought to swim up the rivers from the coastal wintering grounds to
the freshwater breeding sites (Gudmundsson 1961 /// Bengtson 1966).

Timing and routes of migration Harlequins, typically unpaired males, begin to arrive in
Montana in mid- April (Kuchel 1977, Ashley 1994); the earliest record for Glacier National Park is

4 April 1970 on the Middle Fork Flathead River (Kuchel 1977:32). Pairs begin to arrive in late
April and most are present by early May (Kuchel 1977, Ashley 1994). Two-year-old females may
arrive later than older females (Ashley 1994; Kuchel 1977:32). Males begin leaving Montana by
late-May, and are typically gone by late June (Kuchel 1977, Reichel and Center 1993, Ashley
1994). Females may leave by early July if breeding is unsuccessful, and by mid-late July if
successful; they often leave prior to their young fledging (Reichel and Center 1996). Young birds
leave last, beginning in early August, and nearly all birds are gone by the beginning of September
(Ashley 1994).

In Washington, birds amve on breeding streams m late March or early April (Schirato 1993).
In Oregon, birds arrive on the breeding streams in late April, although some have been reported as
early as late February (Latta 1993).

Of 249 Harlequins banded in Montana from 1991-1995, a minimum of 24 have been reported
from Oregon (2), Washington (1), and southern British Columbia (21) including Vancouver Island
and Hornby Island (Ashley 1995, Reichel and Center 1996). Sexes and ages at banding show the
following numbers and percentages observed: adult female (6, 1 1%), aduh males (2, 5%), juvenile
females (9, 7%), and juvenile males (7, 5%) (Ashley 1995, Reichel and Center 1996). Two
females radio-marked in Idaho were located in the San Juan and Culf Islands of Washington and
British Columbia, while one banded bird was reported from northwestern Washington (Cassirer
and Croves 1994)

There are few records of birds between their breeding areas and wintering areas. A single
marked bird has been observed en route between the breeding and wintering grounds (Cassirer
and Croves 1991, Wallen 1993). She was originally marked in Wyoming and observed on the
way back to the breeding stream on Crooked Creek, South Fork Clearwater drainage, in central
Idaho (Cassirer and Croves 1991). She was seen about a week later in Crand Teton National
Park and had nested successfully. The only known wintering bird marked m Wyoming was
observed off San Juan Island in Washington m August 1989; he returned to Crand Teton National
Park as an unpaired male in 1990 (Cassirer and Croves 1991, Wallen 1993).

Migratory behavior It is believed that nearly all one-year-old birds, and some (perhaps most)
two-year-old birds remain in coastal water, not moving to breeding streams until they are 2-4
years of age.

HABITAT PARAMETERS

BREEDINC RANCH TERRESTRIAL

Throughout their range. Harlequin Ducks use a wide variety of habitat types during the breeding
season. Typically they are found on swift, clear streams in a variety of habitats ranging from old
growth to second growth to arctic tundra (Philips 1925, Salomonsen 1950, Bengtson 1966,
Dement'ev and Caldkov 1967, Inglis et al. 1989, Cassirer and Croves 1991, Diamond and
Finnegan 1993, Cassirer and Croves 1994, Ashley 1994). They also apparently breed in coastal
estuaries of British Columbia (Breault 1993), Alaska, and Russia (Portenko 1981). though this
phenomenon is poorly studied or understood.

Overstory In Idaho, Harlequins were strongly associated with mature to old-growth western
red cedar/western hemlock {Thuja plicatalTsiiga heterophylla) forest (Cassirer and Croves

1994). Likewise, in Glacier National Park, ducks were seen primarily in areas with old-growth or
mature overstory (90%); note however that this figure is approximately in proportion with habitat
availability (Ashley 1994). Near Prince William Sound, Alaska, 10 nests were located in 1991-93,
they were all associated with old-growth forest (Crowley 1994). In Oregon, however, old-
growth accounted for only 48% of sightings (Thompson et al. 1993). On the Rocky Mountain
Front of Montana, more birds were seen in pole sized timber (38%) than in other size classes,
including mature and old-growth combined (26%) (Diamond and Finnegan 1993); tree
composition was evenly split between Douglas fir, lodgepole pine and Englemann spruce. On the
Olympic Peninsula of Washington, there appeared to be no selection of particular forest types
(Schirato and Sharpe 1992).

Stream reaches where Harlequins were observed in Idaho were usually not logged or had an
unlogged buffer along the stream (Cassirer and Groves 1994).

Bank composition. In Glacier National Park, most Harlequin observations were adjacent to
banks covered with a combination of trees and shrubs; because this was also the most common
bank cover type in the park, selection was not evident (Ashley 1994). However, pairs did select
for areas with overhanging vegetation (A"^ = 5. 185, p = 0.023) and against areas with undercut
banks {X^ = 4.596, p=0.032) (Ashley 1994). On the Rocky Mountain Front of Montana, birds
were most commonly seen along banks covered with shrub/tree mosaic (23%) or gravel (20%)
(Diamond and Finnegan 1993); locations for most observations did not have overhanging
vegetation (70%) or undercut banks (81%). In Idaho, aduh and brood use of banks, by cover
type, was similar: trees 40%, shrubs 21%, mosaic 20%, grass/forb 7%, rock/sand/silt 6%, and
woody debris 1% (Cassirer and Groves 1994). In Oregon, most banks had trees (41%) or shrubs
(25%) present (Thompson et al. 1993). Undercut banks were present at only 18% of sighting
locations in Oregon (Thompson et al. 1993). Overhanging vegetation was present at 57% of
sighting locations in Idaho (Cassirer and Groves 1994) and 73% in Oregon (Thompson et al.
1993).

In Grand Teton National Park, Harlequins selected banks dominated by shrubs (71%) and
sigmcantly avoided banks dominated by grass/forbs (3%) or trees (1 1%) (Wallen 1987:66).

BREEDING RANGE: AQUATIC

Stream width. On McDonald Creek in Glacier National Park, Montana, Harlequins appeared
to select narrow (<15 m wide) stream locations, although the average stream width was 19 m
(Ashley 1994). In western Montana, 7 other streams with Harlequins ranged fi-om 5-30 m in
width (Fairman and Miller 1990). On the Rocky Mountain Front of Montana, most Harlequins
used streams 6-10 m wide (48%), while the rest used larger (26%) and smaller (25%) streams
(Diamond and Finnegan 1993).

Stream width at most Harlequin observation sites in Idaho was less than 10 m; streams used
by juveniles were significantly smaller than those used by aduhs (Cassirer and Groves 1994),
though a seasonal adjustment was not made. Stream width at most Harlequin observation sites in
Oregon averaged 13.5 m (range 2-50 m) (Thompson et al. 1993). Stream widths of breeding
streams in Iceland ranged from 2-40 m; those streams were typically shallow (0.5- 1.0 m)
(Bengtson 1972).

Stream gradient In western Montana, 7 streams with Harlequins had gradients ranging fi-om

1.8-2.8% (Fairman and Miller 1990). Stream gradients at most Harlequin observation sites in
Oregon were between 1-7%. (62% of observations), while most others were in low (<1%)
gradient areas (33% of observations) (Thompson et al. 1993). On the Olympic Peninsula of
Washington, Harlequins select stream reaches with 1-7% gradient; birds were not present in lower
portions or steep headwater sections of occupied streams (Schirato and Sharpe 1992). In Grand
Teton National Park, Wyoming, Harlequins used the lowest gradient streams in the park,
averaging less than 7% (Wallen 1 987).

On the Rocky Mountain Front of Montana, Harlequins were observed at sites with stream
velocities ranging from 0.8 m/sec to 4.1 m/sec; the average was 1.3 m/sec (n=42) (Diamond and
Finnegan 1993). In Idaho, Harlequin Ducks were strongly associated with swiftly flowing
streams, however, aduhs were found in higher average velocity (1.2 m/sec) locations than were
broods (0.9 m/sec) (Cassirer and Groves 1994). Stream velocity of breeding streams in Iceland
ranged from 0.5-3.0 m/sec (Bengtson 1972).

Channel morphology On McDonald Creek in Glacier National Park, Montana, Harlequins
used straight, curved, meandering, and braided stream reaches in proportion to their availability
(Ashley 1994). On the Rocky Mountain Front of Montana, most Harlequins used streams that
were controlled by v-shaped valleys, either straight (34%) or curved (29%) (Diamond and
Finnegan 1993). In Oregon, 45% of sightings were in straight channels (Thompson et al. 1993).
In Grand Teton National Park, Wyoming, more than 50% of all Harlequin observations were
made in meandering stream channel types (Wallen 1987).

Aquatic habitat In Glacier National Park, Kuchel (1977) found that Harlequin aduhs
selected stream habitats over backwater habitats during the first week of May, but that selection
was reversed dunng 12 June - 2 July (p < 0.01). Bottom types were randomly selected except
during the period 8-14 May when cobble was selected (Kuchel 1977, Ashley 1994). The
strongest selection was for stream reaches with 3+ loafing sites per 10 m (Kuchel 1977, Ashley
1994). However, during brood rearing, 83% of observations during the second week occurred in
backwaters, which increased to 91% by the time broods were 6 weeks old (Kuchel 1977); this is
not evident in Ashley's (1994) data. Broods generally moved downstream as they got older
(Kuchel 1977).

On the Rocky Mountain Front of Montana, most Harlequins used riffles (25%), rapids (24%),
or runs (24%), observations were not separated by season (Diamond and Finnegan 1993).
Similarly, in Idaho, adults used riffle, run, and rapid areas 74% of the time, while broods used
pocketwater and pool/backwater 50% of the time (Cassirer and Groves 1994). In Oregon, adults
also used riffle (21%), run (22%), and rapid (22%) areas equally, while pocketwater, pools,
glides, and backwaters were used substantially less (Thompson et al. 1993).

In Iceland, Harlequins overall selected "calm" water as opposed to "fast" or white" water
(X^ = 42.4, p < 0.001); however, they preferred to feed in "fast" water (X^ = 32.4, p < 0.001)
(Inglisetal. 1989).

In Montana, bays at the mouths of some breeding streams and lakes are occasionally used by
foraging and loafing Harlequins and may provide night roosting areas late in the brood rearing
season (Reichel and Genter 1996). There are muhiple records of broods using lakes in British
Columbia, but the extent and timing of use is unknown (Campbell et al. 1990, Breault and Savard
1991). In Alaska, estuaries and intertidal dehas provided habitat for foraging and loafing

Harlequins (Crowley 1994).

Substrate. In Idaho and Oregon, Harlequins were typically associated with cobble and
boulder substrates (Thompson et al. 1993, Cassirer and Groves 1994); there was no difference
between substrate chosen by adults and broods (Cassirer and Groves 1994). Substrates on the
Rocky Mountain Front of Montana were primarily cobble (62%), boulder (17%), or bedrock
(10%) (Diamond and Finnegan 1993). While most Harlequins were observed on gravel and
cobble substrates in Grand Teton National Park, use of those substrates was not significantly
different than their availability (Wallen 1987).

Woody material was present at 85% of duck sightings in Oregon, with the most structures
being ramps (42%) and drifts (25%) (Thompson et al. 1993). Similarly in Idaho 77% of sightings
were near woody debris (Cassirer and Groves 1991). On the Rocky Mountain Front, however,
less than 40% of the observation locations contained woody debris and 19% contained only a
single piece of woody debris within 10 m (Diamond and Finnegan 1993).

Loafing sites Loaf sites, places where Harlequins will haul out of the water to rest, are
consistently mentioned in the literature and unpublished reports as being important components of
Harlequin Duck stream habitat. In Grand Teton National Park, Wyoming, Harlequins
significantly selected for sites with >3 loaf sites per m, and avoided areas with no loaf sites
(Wallen 1987). On the Rocky Mountain Front, over 70% of Harlequin observations were m areas
with 2 or more loaf sites per 10 m (Diamond and Finnegan 1993). Harlequins in Idaho were
within 10 m of multiple loaf sites 83% of observations for adults and 94% for juveniles (Cassirer
and Groves 1994). Moss covered midstream boulders were used most often in Oregon, with an
average of 5 loaf sites per 10 m at observation sights (Thompson et al 1993, 1993).

In Iceland, Harlequins spent 47% of their time on larger islands, only 24% on rocks
protruding above the river, and <1% on the banks of the river (Inglis et al. 1989)

Quality Streams used by Hariequins in northern Idaho, Montana, and Wyoming (n = 11)
were more alkaline than unused streams (x CaCOs = 58 m/1, x CaCO? = 8 m/1, p = 0.004)
(Cassirer and Groves 1994).

There are two records of broods using glacial streams or lakes in British Columbia (Breault
andSavard 1991).

Quantity. Volume discharge was the most important factor separating used from unused
streams in Pnnce William Sound, Alaska, volume discharge averaged 3.2 m/s on used streams
(Crowley 1994). The largest streams in Prince William Sound were not used by breeding
Harlequins, smaller salmon streams were also avoided by nesting females (Crowley 1994). See
also Causes of death.

Food availability. Streams used by Harlequins averaged a higher standing crop of benthic
macroinvertebrate biomass in Idaho (x = 0.52 g/m^) than unused streams (x = 0.34 g/m^) (Cassirer
and Groves 1994); there was considerable overlap, however, and the differences were not
significant. Bengtson (1966) believed that the distribution of Hariequins in Iceland was
determined by the availability of suitable food, particularly Simuliidae larvae. In Iceland,
Bengtson and Ulfstrand (1971) reported high numbers of non-breeding females on the breeding
streams in 1970; this was correlated with a far below normal standing crop of favored invertebrate
food species. More research revealed that numbers of Harlequins produced from 1977-85 were
correlated with biomass of blackflies {Simulium vittatum) present (Gislason and Gardarsson 1988,

Gardarsson and Einarsson 1993 in Gislason 1994).

Other Concentrated Harlequin Duck use occurs on several stream reaches in Montana
believed to share certain hydrologic characteristics; in particular, stream reaches supporting
notable breeding success are observed to receive locally high rates of groundwater discharge
(Reichel and Center 1996). This has also been noted in British Columbia (Clarkson 1992, Hunt
1993). Some of the densest known Harlequin breeding populations occur in Iceland on the River
Laxa which is the outlet of Lake Myvatn; this lake is spring fed, resulting in very stable flows,
with almost no flooding (Bengtson and Ulfstrand 1971, Gardarsson et al. 1988). Groundwater
discharge may influence Harlequin success by affecting flow regimes, thermal characteristics,
geochemistry and nutrient status, macroinvertebrate fauna, or a interaction of these factors.

WINTER (NON-BREEDING) RANGE

In Iceland, birds primarily use rocky areas with breaking surf (Bengtsonl966). In British
Columbia, they are found in often turbulent waters near rocky islets, shores, and bays where they
fi"equently feed in kelp beds (Campbell et al. 1990).

BREEDING

PHENOLOGY

Pair formation Pair formation in Washington took place on the wintering grounds beginning
in October and was completed by early February (Fleischner 1983). In Iceland, about 10% of
birds were paired by December (Bengtson 1 966). Copulation occasionally takes place on the
British Columbia coast in early April (Pearse 1945).

Nest building. In Iceland, females begin looking for a nest site 1 -2 weeks prior to egg laying
(Bengtson 1966).

Egg laying In Montana, egg laying takes place between 30 April and 4 July, with most
occurring between 10 May and 10 June (Kuchel 1977, Reichel and Genter, unpubl. data). Dates
on which clutches have been found in British Columbia range from 24 May to 24 June;
backdating indicated that the earliest clutch was laid on 17 May (Campbell et al. 1990). Egg
laying in Iceland takes place between 10 May and 8 July, with most occurring in early June
(Bengtson 1966).

Hatching Thompson et al. (1993) reported hatching at two nests on 2-10 June and 10 July.
Kuchel (1977) estimated hatching dates for broods on McDonald Creek, Glacier National Park:
13 of 15 occurred between 27 June and 7 July with the extremes on 1 1 June and 2 August. In
Iceland, young begin to appear in early July (Bengtson 1966). Dates of all ages of brood records
in British Columbia range from 16 June to 13 September, with 53% between 10 July and 12
August (Campbell et al. 1990).

Postbreeding. Young in Montana fledged between 1 5 July and 1 0 September, with most
fledging between 25 July and 15 August (Kuchel 1977, Reichel and Genter, unpubl. data).

NEST SITE

Few nests have been located in the Pacific population; two nests were on rocks, six were on
the ground, two were on cliff faces, two were in piles of woody debris adjacent to streams, two
were in tree cavities, and one was in a cavity on a cliff face. In Montana, a nest was found on a

10

limestone cliff, 6 m above the river (Diamond and Finnegan 1993) and another in a logjam at the
top of a waterfall (Thompson 1985). Cassirer et al. (1993) reported three cavity nests located 0,
0.3, and 14 m from the water (one was 25 m from the main channel). Jewett et al. (1953) reports
a nest on sand and gravel on the Nisqually River, Washington on 26 May 1920; the nest was not
concealed. A nest in Oregon was reported in debris on an overturned stump of alder in mid-
stream (Gabrielson and Jewett 1940). Three additional nests from Oregon were on the ground
and well-camouflaged by low vegetation (Latta 1993, Thompson et al. 1993). In British
Columbia, only 4 nests have been found and were located on: 1) the ground under bushes at the
foot of a small Douglas fir less than 1 m from the creek bank, 2) the ground under a root
overhang, in a depression in a newly formed creek bank; 3) a cliff ledge directly over the river;
and 4) a 2 m tall rock just off an island (summarized in Campbell et al. 1990).

In Alaska, 10 nests were located on steep, southwest-facing, sloping stream banks of small,
first-order tributaries timberline; all were beneath old-growth canopy in shallow depressions or
cavities and associated with woody debris and shrubs (Crowley 1994).

In Washington, interviews with a collector who observed approximately 4 1 nests indicated
that 90% occurred on mid-channel islands which were used in muhiple years (Schirato 1993).
Jewett et al. (1953) reported two nests from Washington, one on a rocky point of a stream, the
other on an open island.

In Iceland, the availability of nest sites may be a secondary factor in determining Harlequin
distribution (following food availability) (Bengtson 1966). They prefer to nest on inaccessible
islands in swift streams; they may also be located in caves or holes in lava or under dense brush
(Bengtson 1966). Of 98 nests in Iceland, 66 were on islands and 32 were on river banks; only 7
were more than 5 m from water (Bengtson 1972). The nests were typically located in dense
shrubs (71 of 98), with some in scattered shrubs (11), grass and forbs (8), and rocks and cavities
(10) (Bengtson 1972).

Nest sites are sometimes reused (Schirato 1994, Thompson 1985).

Harlequins were rarely seen at nest sites; rather, they were almost always seen downstream
(Cassirer et al. 1993).

EGGS

Clutch size In Montana, a clutch of 5 was reported (Diamond and Finnegan 1993), four
clutches of 6, 6, 7, and 7 were reported in British Columbia (Campbell et al. 1990), and 2 clutches
of 7 in Washington (Jewett et al. 1953). In Iceland, 77 complete clutches averaged 5.7 eggs with
a range of 3-9 (Bengtson 1972). There was a seasonal decline in clutch size (Bengtson 1972).
The mean number of eggs to hatch from successful nests was 5.3 (Bengtson 1972). The only
Greenland clutch size reported is 8 (Salomonsen 1950).

Egg laying

When started in relation to nest completion. No availbe information.

Time of day and rate of deposition. Bengtson ( 1 966) followed three nests and found that
intervals between eggs were 2-4 days, with 3 days being the most common interval and with 4
days rare.

INCUBATION

11

Onset of broodiness and incubation in relation to laying. Incubation starts prior to
completion of the clutch (Bengtson 1966).

Incubation period Thompson et al. (1993) reported one nest which took at least 37 days (3
June- 10 July) and another which took at least 24 days (10 May to 3-10 June). Bengtson (1972)
found an average incubation period (laying of last egg to hatching of last egg) of 28 days (n=4,
range 27-29) in Iceland.

Parental behavior.

Roles and attention to eggs and incubating mate. Only females incubate eggs (Bengtson
1966).

Incubation rhythm, duration of attentive periods. Bengtson ( 1 966) reported on a female
who was away form the nest for about 2 hrs. He felt that females only fed about once every 48
hrs.

DEMOGRAPHY AND POPULATIONS

MEASURES OF BREEDING ACTIVITY

Age at first breeding; intervals between breeding Very few 2-year-old males have been
reported on the breeding grounds in North America. Yeariing males make up 1-2% of the
population on the breeding grounds in Iceland (Bengtson 1972, Gardarsson 1979). In Montana,
no males have been reported on breeding streams prior to attaining fully adult plumage at 3 -years-
old (Phillips 1925, Reichel and Genter 1996).

The youngest female known to have bred is a single 2-year-old, although nine additional non-
breeding 2-year-olds have been observed on natal streams and thirteen marked 2-year-olds are
known to have been alive (Reichel and Genter 1996).

Some females on breeding streams apparently do not lay eggs (Bengtson and Ulfstrand 1971,
Dzinbal 1982, Wallen 1987, Cassirer and Groves 1991). Bengtson and Ulfstrand (1971) classified
15-30% (n=48) of adult (by bursae inspection) females as non-breeders, and found that 87% of all
clutches were successful; therefore, approximately 90% of non-breeding females did not even
attempt to breed in Iceland. Additionally, examination of ovaries of 6 non-breeding females
showed that none had lain eggs (Bengtson and Ulfstrand 1971). Many of these non-breeding
"adults" may have been young (2-3 year-old) birds since cloacal examination gives aduh status to
2-year-olds. However, in Iceland, Bengtson (1966) believed that 2-year-old females Hadequins
did not regularly go to the breeding grounds. Dzinbal (1982) estimated that 53-95% of females
not producing broods did not attempt to breed; those resuhs may have been due to use of patagial
markers negatively affecting breeding behavior (Bustnes and Erikstad 1990) Wallen (1987)
reported that some females left the breeding stream at the same time as their mates, unpaired
females arrived about 4 weeks later than pairs, did not breed, and left after 3-5 weeks.

Clutch size Twelve clutches from the Pacific Northwest averaged 6.25 eggs (range 3-7) and
are listed below. In Montana, a clutch of 5 was reported (Diamond and Finnegan 1993), four
clutches of 6, 6, 7, and 7 were reported in British Columbia (Campbell et al. 1990), and 2 clutches
of 7 in Washington (Jewett et al. 1953). Cassirer et al. (1993) reported on 3 nests with 3, 5, and
7 eggs in Idaho. Thompson et al. (1993) reported 2 nests, each with 7 eggs, in Oregon, while
Gabrielson and Jewett (1940) reported a clutch of 6 eggs on 30 May 193 1 on the Salmon River
near Zigzag. In Iceland, 77 complete clutches averaged 5.7 eggs with a range of 3-9 (Bengtson

12

1972). There was a seasonal decline in clutch size (Bengtson 1972). The mean number of eggs
to hatch from successful nests was 5.3 (Bengtson 1972). A single known Greenland clutch was 8
(Salomonsen 1950).

Annual and lifetime reproductive success In Montana during 1989-1994, annual numbers
of ducklings fledged per aduh female averaged 1.60 and ranged from 0.84 - 3.15 (n=230 adult
females) (Reichel and Center 1995), Brood size of Class I-lIb young (Bellrose 1976) averaged

5.1 on the Rocky Mountain Front (Diamond and Finnegan 1993), while throughout Montana, size
lie to fledging averaged 3.57 and ranged from 2.81 - 5.86 (n=103 broods) (Diamond and
Finnegan 1993, Reichel and Center 1995). Average brood size at fledging in Clacier National
Park during 1973-75 ranged from 2 to 4.25 (n=8), while numbers of young fledged per adult
female ranged from 0.1-1.3 (Kuchel 1977:72-73).

Broods ranged from 1-6 in Oregon and averaged 2.7 (n=26) (Thompson et al. 1993, 1994).
These sightings, however, were spread throughout the breeding season and therefore should not
be considered the same as numbers fledged.

In Idaho, number of ducklings fledged per aduh female ranged from 0.7 - 1.3 and averaged

1.2 (n=14); number of females producing broods was 29% in 1990 (Cassirer and Croves 1991,
1994). Average brood size was 3.4 (range 1-7) in Idaho (n=24) (Cassirer and Croves 1991).

In British Columbia, 41 broods of all ages ranged in size from 1-10 (1 Y-3, 2Y-3, 3Y-5, 4Y-
1 1, 5Y-14, 6Y-2, 7Y-1, 8Y-1, lOY-1); the brood with 10 young was apparently from a single
female (Campbell et al. 1990).

In Alaska, numbers of young per breeding female and per adult female were respectively 1.5
and 0.8 in 1979, and 0.6 and 0.3 in 1980, patagial tags on adults $$ appeared to have caused poor
reproductive success (Dzinbal 1982).
Non-breeding frequency of females was 47% in 1979 and 50% in 1980 (Dzinbal 1982).

In Iceland, 1.73 (85:49) and 2.43 (120:49) young per aduh female were successfully raised
respectively during 1975 and 1976 (Cardarsson 1979). In an increasing population in Iceland,
productivity ranged from 0. 1 to 3 .3 (x = 1 . 1 ) ducklings fledged per hen per year over 1 5 years
(Cardarsson and Einarsson 1991). This was similar to that found by Bengtson (1972) who
reported 0.0 to 3.8 young per adult female on 4 rivers during 4 years.

Proportion of total females that rear at least one brood to nest-leaving The proportion of
females successfully raising a brood in a single year, varies widely between years. Reported
numbers range from 12-56% (Bengtson and Ulfstrand 1971, Kuchel 1977, Wallen 1987, Cassirer
and Croves 1991, Reichel and Center 1995). In Montana, 230 females observed between 1989
and 1994 raised 103 broods for an average of 44.8% (range 24-55%) (Reichel and Center 1995).

Sex ratio. Cassirer (1995) found a spring aduh sex ratio of 1 .3 1 : 1 (m:f n = 8 1 ) in 1995 on
Idaho streams. In Banff National Park, Alberta, sex rations varied from 1.37:1 in May to 1.81 in
June (Smith 1996). In Iceland, sex rations on the breeding grounds varied from 54-70% males
during 5 summers in late May - early June (Bengtson 1966, Bengtson 1972, Cardarsson 1979).

In coastal British Columbia the apparent sex ratio is 1.5:1 (544 birds) in winter declining to
1 .4: 1 (297 birds) in March- April (Campbell et al. 1990); this grows to 4.3: 1 in May and by July,
when aduh females are still on the breeding streams, it reaches 18.2: 1 (1633 birds).

LIFE SPAN AND SURVIVORSHIP

13

In Glacier National Park, all mortality of ducklings (through fledging took place in the first
three weeks of life (Kuchel 1977). This is similar to the findings of Bengtson (1966, 1972) who
reported that of 7 broods totaling 37 ducklings, 24 survived 1 week, 19 two weeks, and little
mortality was seen after two weeks. Bengtson (1972) reported that survival of ducklings ranged
from 40-76% on 3 streams over 5 years.

In Montana, 249 Harlequins (39 adult males, 53 adult females, 157 juveniles) have been
banded fi-om 1991 through 1995 (Reichel and Center 1996). Of 58 juveniles marked in 1992, at
least 12 females and 2 males were ahve in 1994, and 8 females and 2 males in 1995; of 42
juveniles marked in 1993, at least 1 female was alive in 1995. Both males known to be alive were
seen on the wintering grounds. Adult males returned to the breeding streams when they were
alive the previous year 53% of the time while females returned at a rate of 57%. The higher
female rate may be due to the fact that a male may mate with a new female, which could lead him
to a new stream, and thus he would not be seen on the previous year's stream.

In Idaho, 63% of aduhs (n=30) returned at least 1 year; male and female rates were not
significantly different (Cassirer and Groves 1994); one duck marked as an adult in 1988 returned
through 1993 (mimmum 7 years old). No ducklings marked fi'om 1988-1991 were re-observed
(n=27). In Wyoming 40% of marked aduhs returned to breeding streams (Wallen 1993). At least
5 females of 103 ducklings banded in 1987-1990 have returned and nested successfiilly (Wallen
1991). The oldest known Wyoming bird was marked as a duckling in 1985 and recaptured in
1991 (Wallen 1993). In Alaska, 30% (8) aduh females and 30% (3) of aduh males marked were
relocated the following year (Dzinbal 1982:62).

In Iceland, 64% (20) aduh females and 48% (13) of aduh males, marked with nasal discs,
were relocated the following year (Bengtson 1972). Hatching success in Iceland averaged 87%
and ranged fi'om 84% to 91% in four years (Bengtson 1972).

CAUSES OF MORTALITY

Causes of death. In Montana, high water during early summer runoff was associated with
low productivity (Kuchel 1977, Diamond and Finnegan 1992, 1993, Reichel and Genter 1993,
1995). Wallen (1987) reported that following a severe July rainstorm which raised a creek level
0.6 m within 2 hours, both broods seen prior to the storm were never seen again; however, he
generally felt that drought in Grand Teton was more limiting to reproductive success than
flooding. Dzinbal (1982) reported higher spring run off was associated with lower reproduction
in a two-year study in Alaska. In Idaho, productivity was negatively correlated to June stream
flow (r = -0.93, p = 0.006) (Cassirer and Groves 1995). It is currently not understood what
causes this correlation. Possibilities include females not nesting due to high water and/or poor
feeding; destruction of nests within the floodplain; or loss of juveniles due to drowning, being
separated from the female, inability to feed effectively, or hypothermia.

Bengtson (1972) found very low duckling survival coincided with adverse weather and very
low abundance of blackflies, their preferred food in his study area.

In coastal waters. Harlequins are occasionally caught by large mussels and clams by the bill
and drowned (Turner 1886 //; Philips 1925)

Exposure andpredation Predation on eggs by river otters and black bears has been reported
from Washington (Jeff Foster, unpubl. data, in Schirato 1993).

14

Following mink (Musteia vison) introduction to Iceland, Harlequin populations substantially
declined in several areas, and changed nesting sites in others (Bengtson 1966). Predators took 9
nests in Iceland (n=89) and included Raven (5), mink (2), Arctic Skua (1), and arctic fox (1)
(Bengtson 1972). Additionally 2 nests were deserted and I failed to hatch (Bengtson 1972).
Arctic Skuas were seen taking 2 chicks in Iceland (Bengtson 1972).

RANGE

Dispersal from natal stream All juveniles leave the natal stream soon after fledging (Reichel
and Center 1996, Cassirer and Groves 1994). Of 100 ducklings banded in Montana in 1992-93,
seven males marked as juveniles were seen only on the coast, none have been reported from their
natal stream (Ashley 1995, Reichel and Genter 1996).

In Alaska, one brood was reported to use a Stellar Lake when very young, moving down to
Stellar Creek when older, and finally used Stellar bay and the lower tidal portion of Stellar Creek
when Class IIc-3 (Dzinbal 1982).

Fidelity to natal stream. Of 100 duckling marked in 1992-93 in Montana, 14 females are
known to have survived at least 2 years. Of the 14 surviving females, 5 were reported only from
their natal stream, 1 only from the coast, and 8 both on the coast and the natal breeding stream.
Seven males marked as juveniles were all seen only on the coast; none have been reported from
their natal stream (Ashley 1995, Reichel and Genter 1996). In Glacier National Park, 2 of 5
ducks banded as juveniles in 1974 returned to the natal stream in 1976; both were females
(Kuchel 1977).

No ducklings marked from 1988-1991 in Idaho were re-observed (n=27).

POPULATION STATUS

Estimates or counts of density Densities of Harlequins on breeding streams range from 0.05
pairs/km on a stream in Montana (Diamond and Firmegan 19930 up to 8.5 pairs/km on part of the
Laxa River in Iceland (Bengtson and Ulfstrand 1971). In Montana, pair density on a 16 km
section of McDonald Creek was 0.67 pair/km in 1974 and 0.91 pair/km in 1975 (Kuchel 1977).
On the Rocky Mountain Front, densities ranged fi-om 0.05 pairs/km to 0.21 pairs/km (Diamond
and Firmegan 1993).

In Idaho, pair densities averaged 0. 19 pairs/km (range 0.08-0.57) of occupied streams
surveyed (Cassirer 1995). From 1990 through 1992, densities there averaged 0.06-0.53 pairs/km
(x= 0.22) (Cassirer 1993). In Oregon, densities of aduhs per km surveyed ranged fi-om 0.07 to
1.21; densities per km surveyed including juveniles ranged from 0.07 to 2.37 (Thompson et al.
1993, 1994).

On the Bow River in Banff National Park, densities observed were the highest known fi-om
streams in North America, ranging from 2.4 ducks/km on a 15 km reach to 6.2 on a 16 km reach
(Smith 1996).

On Kodiak Island, Alaska, density of breeding Harlequin pairs ranged from 0.63 pairs/km
along the Ayakulik River to 1.98-7.24 birds/km in 3 coastal bays (Zwiefelhofer 1994). Dzinbal
(1982) reported 1.3-1.8 pairs/km on two small coastal streams in Alaska.

On the Laxa River in Iceland, Harlequins are apparently at densities higher than other known
stream populations (Bengtson 1972). Twenty populations in Iceland ranged fi-om 0.2 to 8.5

15

pairs/km, with an average of 0.9 pairs /km (Bengtson and Ulfstrand 1971, Bengtson 1972).

In eastern Siberia (Kistschinsky 1968 /// Bengtson 1972) found 1.1 pairs/km and 0.8 - 1.2
broods/km.

Numbers. Numbers estimated by most recent publications and reports are described in Table
4. The largest reported single Harlequin Duck occurrence (see Breeding Range) is from the Bow
River drainage in Banff National Park where 215 individuals were calculated to occur during 1995
using a mark/resight model (Smith 1996).

Table 4. Estimated numbers

of Harlequin Ducks.

Location

Estimated

Breeding

Population

Minimum
# Pairs

Estimated
# Pairs

Citation

Atlantic Ocean

?

Greenland

?

Iceland

?

North America

<1,000

Goudie 1991

Pacific Ocean (Asia)

Russia

50,000 -
100,000

Japan

?few

Pacific Ocean (North America)

165,000

Goudie et al. 1994

Lower 48 U.S. States

523

758

Cassirer et al. 1996

Washington

274

399

Schirato 1994

Montana

110

159

Reichel and Genter
1996

Oregon

50

72

Thompson et al. 1993

Idaho

48

70

Cassirer et al. 1996

Wyoming

40

58

Cassirer et al. 1996

Trends. Little data is available either long or short term. The Atlantic population has
undergone and is continuing to undergo significant declines (Harlequin Duck Working Group
1993). In the North American Pacific populations, the trend is less clear cut. Christmas bird
counts in British Columbia show declines at 5 locations and increases at 3; the increases may be

16

due to increasing numbers of observers in urban areas (Harlequin Duck Working Group 1993).
In Alberta breeding Harlequins are significantly declining on the Maligne River in Jasper National
Park (Harlequin Duck Working Group 1993) Seven streams in Northern Idaho appear to be
stable though 1 stream shows a decrease and one an increase; all populations are relatively small
(Cassirer 1995). In Montana, the long term trend appears downward. Occurrences with larger
populations (>5 pairs) appear to be stable over the last 4-8 years, while some small occurrences
appear to be declining or have recently gone extinct (see Historic Changes); however, this has not
been statistically analyzed. In Wyoming, breeding populations appear stable in Grand Teton
National Park (Harlequin Duck Working Group 1993).

POPULATION REGULATION

A simple model using guesstimates for values of survival and fecundity was developed by
Goudie and Breauh (1994). It estimated that at 85% aduh survival, the population would grow at
6%/year. Simulations indicate that the model was most affected by aduh survival; an increase of
3% mortality may not be sustainable over the long term (Goudie and Breault 1994).

CONSERVATION AND MANAGEMENT

EFFECTS OF HUMAN ACTIVITY TO HARLEQUIN DUCK POPULATIONS,

REPRODUCTION, AND BEHAVIOR

Disturbance on the breeding grounds. On and near shore. Kuchel (1977) found that broods
less than 4 weeks old avoided areas with human access and selected areas that were distant from
access and inaccessible (p<0.05) on McDonald Creek in Glacier National Park. This was not true
of adults during May and early June when fewer park visitors were present. More recently,
Ashley ( 1 994) found Harlequins used inaccessible areas in greater proportion than their
availability, though not significantly so; his data is conservative in that surveys took place in the
early morning prior to the vast majority of visitor use. Most Harlequins left accessible stream
reaches when visitor use reached more than minimal levels. Ashley (1994) found males were
displaced by human activity to a greater extent than females. He speculated that this may be due
any or all of three reasons. First, females were likely born in Glacier National Park with its many
visitors, and are more habituated to humans than males which were likely born at other locations.
Second, females spend more time each year, during higher visitation periods, than males on
McDonald Creek and may be more habituated to human contact. Third, females are more
cryptically colored and less likely to attract casual visitor attention.

On the Rocky Mountain Front in Montana, only 1 5% of sightings were in areas that were
inaccessible (>50 m fi"om established areas of human activity, not accessible by trail) (Diamond
and Finnegan 1993). Of the accessible areas, 5 1% were >50 m from a trail, 21% were 10-50 m
from a trail and 13% were <10 m from a trail; it should be noted that >90% of this area is
roadless. Visitor use is highest along the South Fork Sun River, where monthly trail use is 500
people in July and August (Diamond and Finnegan 1993).

In Grand Teton National Park, Wyoming, 95% of Harlequin observations were in backcountry
areas, accessible only by trail (Wallen 1987). Within the backcountry however. Harlequins used
areas with moderate (5-9 people/day) to heavy (>10 people/day) human use more than lesser used
areas; Wallen (1987) suggested that may have been the result of the presence of many high

17

gradient, inaccessible stream reaches which lacked the habitat features Harlequins preferred.

In Yellowstone National Park, a three-year study was done to assess visitor impacts to
Harlequin use at LeHardy Rapids where it appeared that duck use had decreased due to high
visitor use (McEneaney 1994). The area was closed to visitors fiom 1 May - 7 June 1991-1993
and Harlequin Duck use increased; a historical nest site in the immediate vicinity was not
reoccupied (McEneaney 1994). Beginning in 1995, visitors were to be confined to a boardwalk.

In Idaho, Harlequin Ducks were typically found at sites more than 50 m from road or trail
access (aduhs = 75%, broods = 80%) (Cassirer and Groves 1994). Pair densities there were
lowest on streams most accessible to human activity (Cassirer and Groves 1991). In Oregon,
duck sightings were much closer to sites with established human activity, with 48% within 10 m
(roads 48%, fishing 29%, hiking 19%) (Thompson et al. 1993).

In Washington, a cavity nest with the opening 2.4 m high was located 1 .3 from a trail (in
1991) and within a back country corral (1992); the depth of the nest cavity (61 cm) prevent the
hen fi'om seeing outside and hid her from view (Cassirer et al. 1993). Two nest cavities in Idaho
however, were located in areas seldom used by humans, about 150 m from logging roads
(Cassirer et al. 1993),

In Jasper National Park, visitor use by hikers, nature tours, fishermen, tourists, and boaters
(see below) on Maligne River drainage has increased substantially in the past decade; during that
period Harlequin Duck numbers have also decreased substantially (Clarkson 1992, Hunt 1993). It
was felt that disturbance was likely the cause of the decline and recommendations were made to
revise the method of controlling rafting including: closing particular river reaches to boating and
other human activity, and not issuing new business licences/special activity permits which would
increase the current level of human activity in the area (Clarkson 1992).

Within the stream. Cassirer and Groves (1991) reported that 5 of 1 1 streams where Harlequin
breeding was reported or confirmed during 1988-1990 were closed to fishing or did not open to
fishing until 1 July.

Wallen (1987) reported that fishing seemed more disruptive to Harlequins than hiking, and
they avoided humans on the bank or in the stream bed. Birds would typically swim or dive
downstream past people, keeping partially submerged when past and watching behind them as
they moved out of the area. Two hens with broods abandoned a section of one creek when
fishing pressure increased in August; they moved to a nearby creek which drained into the same
lake, and where fishing was not observed (Wallen 1987).

//; boats. Prior to significant raft and canoe use on rivers in Jasper and Banff, Holroyd (1979)
warned of potential negative effects of intensive river use on Harlequin Ducks. Since that time,
commercial white-water rafting on the in Jasper National Park has exposed pre-nesting, and
perhaps nesting, ducks to frequent disturbance (Clarkson 1992, Hunt 1993). Only six commercial
trips took place there in 1986; commercial use increased to over 1500 trips/year by 1990
(Clarkson 1992, Hunt 1993). This was significantly correlated with declining Harlequin Duck
numbers during the period 1986-1992 (Hunt 1993). Additionally, the mean monthly abundance
of Harlequin Ducks is significantly and negatively correlated with number of rafting trips per
month (May, June, July) from 1986-92 (Hunt 1993).

On the Maligne River in 1993, Harlequins were displaced by rafts in 87% of 91 encounters;
duck reactions included flying (60%) and swimming (19%) away from the rafts (Clarkson 1992).

18

Birds usually took flight if a raft was on a collision course with a bird, was within 1-15 m of a
bird, or if the raft crew was acting "boisterously" as they passed the duck (Clarkson 1992). Hunt
(1993) recommended closure of the river to rafting to attempt to restore historic population levels
of Harlequins. He listed other less commercially disruptive actions which could possibly help
stem the decline in Harlequins including: 1) reducing the amount of time each day rafting was
permitted; 2) reducing the times per day launches were allowed, and 3) reducing the length of the
season that river use is permitted (Hunt 1993).

On the Bow River in Banff National Park, reaction to canoes by Harlequins was considerably
less (Smith 1996). In 158 encounters, 62.6% of ducks had no reaction, 16.5% swam away,
1 1 .4% flew away, and 9.5% hid (Smith 1996). The considerable difference in reactions between
ducks on the Bow and Maligne Rivers is probably due to the fact that the Bow is very much wider
and splits in channels in numerous locations (Smith 1996).

Cassirer and Groves (1991) reported that nesting appeared to occur on stream reaches above
those used by rafts on the two regularly boated Harlequin Duck streams in Idaho. Heavy white-
water rafting is believed to have caused the extirpation of Harlequins on the Methow River m
Washington (Brady pers. comm. //; Clarkson 1994).

Noise. No specific information found.

Collecting and trapping. Collecting permits have been issued in Montana (1), Washington,
and Alaska. In Washington, permit for 1 5 was issued as recently as 1 992, with permits for up to
50 issued in previous years (Schirato 1993). There is a market for Harlequins in the avicultural
trade, with paris valued at $2,000 or more (C. Pilling, aviculturalist, pers. comm., in Harlequin
Duck Working Group 1993).

In Iceland, egg collecting was extensively carried out in some areas through the mid-1960s,
both for consumption and sale for raising, it is now be prohibited (Bengtson 1972).

Capture of 465 Harlequin Ducks in British Columbia coastal waters resulted in 5 mortalities, 3
by drowning and two by heat prostration (Clarkson and Goudie 1994). In Montana, mist netting
over 250 Harlequins on breeding streams has resuhed in 1 death by drowning of a duckling and 1
leg injury of an aduh.

Shooting Hunting was the likely cause of the decline of the eastern North American
Harlequin Duck population (Philips 1925, Palmer 1949). This was probably because they are less
wary than other sea ducks while on the coast (Philips 1925, Palmer 1976) and they forage in
shallow water close to shore.

In Alaska, Harlequins are harvested by both recreational and subsistence hunters (Rothe
1994). The extent of hunting in the Pacific North American population appears low, with the
exception of a few local areas in Alaska. No band returns from hunting have been reported in
over 249 birds banded on breeding areas of Montana, however, a banded bird was found to have
holes in the webbing of the foot caused by pellets from a shotgun (Reichel and Center 1994).

Fishing. Harlequins have been found entangled in fishing line in Glacier National Park on
McDonald Creek (Ashley 1994), and in Jasper National Park on Maligne Lake (Clarkson 1992).
A Harlequin has also been found with a fish hook lodged in its throat (Cassirer, pers. comm., ///
Clarkson 1992)

Pesticides and other contaminants/toxics. Thousands of Harlequins were killed or injured as
a result of the Exxon Valdez oil spill of 24 March 1989 (Patten 1993 /// Clarkson 1994). Later,

19

productivity in western Prince William Sound, where oil remained, was nearly zero during 1989-
1993; reproduction was substantial in un-oiled portions of eastern Prince William Sound (Patten
1994). Petrochemicals were found in the proventriculus, liver and bile in Harlequins in western
Prince William Sound and southwestern Kodiak Island; these were probably introduced via
feeding on blue mussels {Mytilus adulis), an important food of Hariequins (Patten 1994). A
relatively small oil spill in 1991 by the TenyuMaru threatened approximately 10% of the
Harlequins wintering in Washington (G. Schirato pers. comm. /// Clarkson 1994). Even the
remote western Aleutian Islands, where most Harlequin winter, sparse , but wide-spread oil
pollution is a potential threat (Byrd et al. 1992).

Wintering Harlequins concentrate in several areas along the Pacific coast for feeding and molt.
Among these concentration areas are the east shore of Vancouver Island where toxic pollutants
are abundant (Waldichuk 1983 in Clarkson 1994). and commercial, industrial, and recreational
development are growing rapidly.
Degradation of habitat: breeding and wintering.

Breeding. In 1992 a gas pipeline project was started, crossing the Moyie River in Idaho 8
times (Cassirer 1995). Harlequins are known to use this stream and a study was begun when
siltation was noted from construction. The siltation caused a decline in macroinvertebrates fed on
by Harlequins, and there no young were successfully raised the year the construction took place
(Cassirer 1995). Recovery of macroinvertebrates was expected to occur within a year and
Harlequins successfully bred the following year. The effects of the construction could have been
minimized by doing the work in late summer (after 1 September) or fall. The long term effect of
the loss of one years production on the very small population present is not known (Cassirer
1995). However, several items were noted, including the fact that Harlequins attempted to breed
(unsuccessfully) despite the disturbance, and did not move to nearby streams.

MANAGEMENT
Federal

Fish and WildUfe Service. Neither the Atlantic or Pacific populations are listed as
Threatened or Endangered in the United States. The Harlequin Duck was listed as a Category 2
Candidate Species prior to 1996 when that Category was administratively eliminated. It is legally
hunted in the Pacific states and provinces under the Migratory Bird Treaty Act and state,
provincial and federal regulations. Hunting is closed on the Atlantic flyway.

National Park Service. A seasonal boating closure was instituted on McDonald Creek
above Lake McDonald in Glacier National Park in 1995 to protect Harlequin Ducks; the stream is
closed to boating from 1 April though 30 September (J. Ashley pers. comm). No boating on
rivers is allowed in Yellowstone National Park to protect wildlife values. No U.S. National Park
Service Harlequin Duck management plan exists.

Forest Service. The Harlequin Duck is a Sensitive Species in the Northern, Rocky Mountain,
and Pacific Northwest Regions. Forest Service policy states that sensitive species should be
managed to ensure that populations do not become threatened or endangered.

States/Heritage Programs. The Harlequin Duck is classified as a state sensitive species in
Oregon, a priority habitat species in Washington, and a species of special concern in Idaho and
Montana.

20

Other legal status The Atlantic population of the Harlequin Duck is listed as Endangered by
the Canadian Wildlife Service.

Mitigation procedures. None found.

ONGOING RESEARCH THAT RELATES TO ANY OF THE
TOPICS LISTED ABOVE

I. Goudie and C. Smith will begin a banding study in 1996 on the Elbow, Sheep and Highwood
Rivers, Alberta, in response to a commercial rafting permit application on the Elbow.

Smith (1995) has begun a multi-year study in 1995 to assess the impacts of upgrading a single-
lane Highway to a split double-lane highway beginning in 1996. Banding began in 1995 when 41
adult and 3 ducklings were marked. This site is a very large river compared to Montana
Harlequin streams, with perhaps 4 times as many ducks as the largest Montana population
(McDonald Creek). Potential impacts on the site include: changes in th natural flow regime,
changing in macroinvertebrate food base; increased recreational use, and interruption of stream
connectivity by installation of culverts rather than bridges (Smith 1996).

E. F. Cassirer is continuing to survey and monitor Harlequins in Idaho. Currently no marking is
taking place. This will add more information about numbers, trends, and productivity.

S. Patton is completing data workup on effects of oil spills in coastal areas on Harlequm Ducks.

I. Goudie and collaborators are continuing to study survival and fidelity to wintering populations
in Bristish Columbia. Winter survival and site fidelity are also being studied in Washington (G.
Schirato). This data will nicely dovetail with our breeding data to get a complete picture of
survival and site fidelity for population modeling.

W. Hunt and P. Clarkson continue to study the effects of rafting on Harlequins in Jasper National
Park. They are also banding birds for site fidelity and movement, but have not banded for as
many years as we have in Montana nor have they banded many juvinales.

ME. Brown is begining a master's thesis project which will be a rather fine-grained study of
parental kinship and investment, and instances of extrapair fertilizations. Specifically she would
like to (1) assess patterns of relatedness of females breeding near one another, which harks to
philopatry and the population, genetic, and behavioral consequences thereof; (2) observation on
parental behaviors, to address observations of varying brood-abandonment timing and examine
parental cost-benefits, etc., and (3) assay broods for extra-parental contribution (either from
female egg-dumping or male extra-pair paternity).

D. Esler is working on genetic analysis of North American Pacific coast Harlequin to determine
extent of genetic mixing in different winter (primarily) and some summering areas. He hope to
determine whether separate Harlequin Duck metapopulations exist within the western North

21

America region.

PRIORITIES FOR FUTURE RESEARCH

The following are among the highest fliture research priorities and are primarily a subset of those
listed by the Harlequin Duck Working Group (1993) and Cassirer et al. (1996).

1) What are the impacts of human disturbance on breeding and wintering Harlequin Ducks?

Several independent studies have documented the sensitivity of Harlequin Ducks to human
disturbance, primarily through the relationship of sighting locations to accessibility of the
locations (Kuchel 1977, Wallen 1987, Diamond and Finnegan 1993, Cassirer and Groves 1991,
1994, Clarkson 1992, Ashley 1994). Specifically, boating has been shown to have a significant
negative correlation with numbers of ducks present in one area on a medium-sized stream
(Clarkson 1992, Hunt 1993). Observations in other areas tend to support this conclusion
(Cassirer and Groves 1991, Brady pers. comm. in Clarkson 1992) in this may not be the case in
very large streams (Smith 1996). Fishing and human presence has also been suggested as a cause
of disturbance with specific examples, but without statistical data analyses (Wallen 1987,
McEneaney 1994, Cassirer and Groves 1991).

Wide-scale analyses have not yet been attempted nor have analyses on the effects of most specific
kinds and amounts of human activities except boating. Several specifics should be done to
address these questions.

First, wide-scale data on Harlequin streams should be gathered including productivity, population
size, length of stream segments used during pair and brood seasons, categories and locations of
land ownership of the streams, hydrogeological properties of the streams, habitat of the streams,
and current human use of the stream (by roads, trails, structures, activity, etc.). A first step will
be to see what is available and what needs to be gathered in the field. Some such as population
size, and length of stream segments used is known for many streams, while others need
preliminary data gathering to determine what is available (hydrogeological properties, habitat of
the streams, and current human use). We can then randomly select unused and/or unknown
streams that fit physical parameters of used streams and compare them in respect to kind and
amounts of disturbance/accessibility. See Proposals 2 and 3.

Second, responses to humans could be evaluated by recording initial responses to surveyors. This
would only give immediate, in sight response of birds which were seen; presumably some would
react prior to the surveyor seeing them and not be observed. Nor would it revel how much time
or distance the bird moved in reaction to the disturbance. A more precise but intrusive method
would be to use radiotelemetry on the birds. Radio-telemetry would also provide more accurate
data on use of habitat types and locations relative to human development/access points. See
Proposal 4.

22

Third, if actions are undertaken on Harlequin streams, they should be monitored to determine
there effects. This allows us to learn the effects of various actions and not repeat mistakes in the
future. To determine effects of specific land management or development actions on Harlequin
streams, the action should be proceeded by at least two years of baseline marking and surveying
for population size and productivity, habitat evaluation, and pre-action levels of human activity
and development. The population should be monitored during and following the action to
determine the effects of the action. Actions which particularly need attention include road,
campsite, and trail construction and upgrading, including any increased accessibility and changes
in human use of the area; actions which could resuh in changes to flow regimes or water quality,
such as mining, road building, timber harvest, industrial development, and water/hydroelectric
development; changes in fishing regulations which could change fishing use of the area; building
of structures such as industrial areas, dams, or houses which will increase the access and use of a
Harlequin stream. Possibilities for mitigation and habitat restoration can be explored during these
projects.

2) What is the extent and nature of movements in breeding and wintering areas?

This information is needed to determine the possibilities for naturally recolonizing new and
historic Harlequin occurrences; naturally supplementing existing occurrences, particularly small
populations, and how strong natal and adult fidelity to particular sites are. All these are needed to
successfully model Harlequin populations and their stability, with both breeding and wintering
grounds data incorporated.

Radio-telemetry may give quick results from the standpoint of local daily movements,
however, I expect that long distance (>5 km) movements are relatively rare and with limited
numbers of ducks radioed may not be best for long distance movement detection. For long
distance and moves between years, visibly marking birds is best. For association to natal areas,
this will be a long term project, but Montana has the best start with 250 birds banded on the
breeding grounds since 1992. With the start we have now, I estimate sufficient information for
preliminary modeling will be available following the 1996 field season if funding is received, and
good information could be available following the 1998 field season for final modeling.

For the wintering grounds, much data is available and is currently being collected in
Washington, Alaska, and British Columbia. It should be available within 2 years with sufficient
information to use in detailed population modeling. For an accurate model, information is
necessary from both the breeding and wintering grounds. See Proposals 1, 4, 5.

3) Are distinct metapopulations (such as a Rocky Mountain breeding population) identifiable
within the Pacific range of the Harlequin Duck?

The degree of genetic differences among and within wintering and breeding subpopulations would
allow an assessment of the appropriate management units for various Harlequin conservation
strategies. Dan Esler, Alaska National Biological Service is currently examining this question,
primarily for wintering areas, but he is also examining blood samples we are providing from

23

Montana.

4) What are the critical habitat components hmiting Harlequin Duck breeding and wintering
populations?

Harlequin Ducks use a wide variety of habitats on the breeding grounds, from forests to tundra.
Habitat usage should be documented over a large number of study areas to identify common
habitat components and compare them to available habitat; there are both large and small scale
considerations here. See Proposals 2, 3, 4.

5) How and why do productivity and survival change over time and among areas, and what are
the relative impacts of these changes on populations?

Long term studies are needed to determine population parameters and then incorporate them into
population models (with information from movements on the breeding and wintering grounds).
These parameters include; productivity; age-related survival; recruitment; age(s) at first breeding
and/or successful breeding; age(s) last breeding; life expectancy; and causes and timing of
mortality. These can only be done with long-term studies involving marked birds on both the
breeding and wintering area. Currently we are in a good position to complete these studies given
that we already have 4 years of data and coastal populations are currently being marked and
studies. See Proposal 1 .

The most difficult question is the causes of mortality, which is not tractable given current
technology. If and when small, long range mortality transmitters are available for ducks, this
should be pursued.

6) What are the characteristics of Harlequin Duck migration? How well defined are migratory
staging areas and migration corridors?

This question may not be tractable given current technology. If and when small, long range
mortality transmitters are available for ducks, this should be pursued. Some answers may come
from large scale marking of individuals such as in Proposal 1, and perhaps by relocating radioed
birds in Proposal 4.

RESEARCH PROPOSALS TO ADDRESS THE MOST CRITICAL
DATA GAPS

List of Attached Proposals

1 . Harlequin Duck Population Parameters, Site Fidelity, and Movements

2. Review of Hydrologic and Geologic Data Availability for Harlequin Duck Breeding Streams in
Montana.

3. Large scale evaluation of characteristics of occupied versus unoccupied Harlequin Duck

streams in Montana.

24

4. Radio-telemetry study of the effects of disturbance on movements and habitat selection by
Harlequin Ducks.

5. Site fidelity, productivity, survival, and recruitment of Harlequin Ducks in western North
America: Modeling the available data.

ACKNOWLEDGMENTS

E. F. Cassirer lead the Northern Rocky Mountains Working Group in compiling the data and
literature on surveys and research priorities for the region, with considerable input from R. Wallen
and E. Atkinson. Many people helped to complete the data analyses, map preparation, and
literature compilation reported here. C. Jones, K. Jurist, D. Dover, M. Beer, J. Hinshaw, and D.
Center of the Montana Natural Heritage Program all contributed to the time and effort needed to
finish this report.

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