| Summary: | Breeding habitat of Harlequin ducks (Histrionicus
histrionicus) was studied in eastern Prince William Sound,
Alaska, during 1991 - 1993. Streams in Prince William
Sound were surveyed for Harlequin ducks and monitored with
mist nets. Physical characteristics of 24 Harlequin
breeding streams were compared to those of 24 streams not
used for breeding using 2 sample, principal components and
logistic regression analyses. Nests were located using
radio-telemetry of marked females.
Harlequin ducks resident in eastern Prince William
Sound selected the largest anadromous salmon streams
available for nesting. Volume discharge of breeding
streams averaged 3.2 m��/s and was the most important factor
in habitat variation between streams used and not used by
breeding Harlequins. Expansive estuaries and intertidal
deltas present at the outflow of large streams were
important foraging and loafing areas of Harlequin ducks.
Although nesting females generally avoided smaller salmon
streams their intertidal estuaries were often used for
foraging by females and molting males. The largest streams
in Prince William Sound, glacially fed rivers, were not
used by breeding Harlequins.
Ten nest sites of Harlequin ducks in eastern Prince
William Sound were located on southwest facing, steeply
sloping banks of small, first order tributaries near
timberline elevation. Nests were associated with woody
debris and shrubs, in shallow depressions or cavities, and
were beneath the canopy of old growth forest. Microhabitat
produced by a southwest aspect, snow shadow provided by the
forest canopy, and sloping stream bank may provide nesting
sites earlier in the spring compared to surrounding areas. === Graduation date: 1994
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