Graduate Thesis Or Dissertation
 

Ecology of harlequin ducks in Prince William Sound, Alaska, during summer

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/ng451m068

Descriptions

Attribute NameValues
Creator
Abstract
  • Harlequin ducks (Histrionicus histrionicus) were observed during the summers of 1979 and 1980 in Sawmill Bay, northeast Prince William Sound, Alaska. Harlequins were associated with a short, medium gradient, non-glacial stream (Stellar Creek) also used by salmon. Although harlequins nested along Stellar Creek, they apparently did not establish home ranges there during the prenesting period, and both courtship and copulation occurred in the bay. Pairs were most numerous.in the bay in mid-late May; 15 pairs were recorded in 1979, and 14 pairs were observed in 1980. Laying occurred from about 26 May - 17 June, and hatching took place from 3-15 July. Females lost weight during the incubation period, but gained weight the remainder of the. summer. The non-breeding frequency among females was estimated as 47% in 1979 and 50% in 1980. The application of patagial tags, however, appeared to reduce production. Following nesting, males generally deserted Sawmill Bay for comparatively exposed moulting areas, Females mostly remained in the bay until midlate August. Use of habitats by harlequins varied with time of day, and activity budgets varied with habitat. Paired harlequins during prenesting and laying (10 May - 21 June) spent about 47% of their time near rocks and headlands, and about 26% of their time each in Stellar Creek and in lee (i.e. protected) waters. Unpaired harlequins (22 June - 15 August) were rare in lee waters (<3%); unpaired males spent about 77% of their time on rocks and about 20% of their time in Stellar Creek, while unpaired females spent about 43% and 55% of their time on rocks and in Stellar'Creek, respectively. Harlequins primarily rested on rocks and headlands, while lee waters seemed important mostly for social spacing among pairs. Stellar Creek was the focus of nearly half to practically all of the feeding activity of harlequins. Early in the summer they fed primarily on marine invertebrates in the intertidal delta of the creek, but in July they moved upstream into the spawning beds of the arriving salmon, where they fed predominately on loose, drifting roe. Paired females spent more time feeding (21% vs 13%), but less time resting (41% vs 46%) and interacting (1% vs 3%) than did their mates. Unpaired females spent slightly more time feeding (15% vs 13%) and in locomotion (13% vs 10%), but less time preening (6% vs 3%) than did unpaired males. The large proportion of time harlequins spent resting was tentatively attributed to a strategy of minimizing energy expenditure, versus one of maximizing energy intake.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items