Author : David W. Crowley
Publisher :
ISBN 13 :
Total Pages : 128 pages
Book Rating : 4.:/5 (36 download)
Book Synopsis Breeding Habitat of Harlequin Ducks in Prince William Sound, Alaska by : David W. Crowley
Download or read book Breeding Habitat of Harlequin Ducks in Prince William Sound, Alaska written by David W. Crowley and published by . This book was released on 1993 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 m3/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.