Title: Breeding Ecology of Harlequin Ducks in Prince William Sound, Alaska
Project Year and Number: 1992: R071
Other Fiscal Years and Numbers for this Project: None
Principal Investigator (PI): Dave Crowley, Alaska Department of Fish & Game
Assisting Personnel: Samuel Patten
Research Location: Prince William Sound
Restoration Category: Damage Assessment
Injured Resources Addressed: Harlequin Ducks
Abstract: The Exxon Valdez oil spill of March 24, 1989, heavily impacted the harlequin duck (Histrionicus histrionicus) population in western Prince William Sound. The Sea Duck Study in Bird Number 11 reported sublethal symptoms of petroleum hydrocarbon contamination, including an apparent reproductive failure in harlequin ducks (Patten 1991).
Harlequin ducks breed along mountain streams in coastal old growth forests in Prince William Sound. Harlequin ducks have a relatively low reproductive rate because of small brood size (3.4 ducklings/brood in Prince William Sound), second year sexual maturity and low breeding frequency (<50%) of hens (Dzinbal 1980, Crowley 1991). Harlequin ducks have high fidelity to breeding and wintering areas (Bengtson 1972). Kuchel (1977) stated that several consecutive years of very low production or injury to winter and breeding habitat could completely eliminate a local harlequin duck population.
The Harlequin Duck Restoration Project (Crowley 1991) documented successful harlequin duck reproduction in 1991 in unoiled northern, eastern, and southern (referred to collectively as "eastern" unless specified) Prince William Sound. This area was not impacted by the oil spill. However, large tracts of harlequin duck breeding habitat in old growth forest of prime commercial value are currently scheduled for logging in Prince William Sound.
The impaired status of harlequin duck populations in the Exxon Valdez oil spill area of western Prince William Sound may necessitate protection and management of populations in the non-impacted areas of Prince William Sound. A large population of harlequin ducks in eastern Prince William Sound could provide a pool of immigrants to western Prince William Sound. Recolonization of the oil spill area by reproducing harlequin ducks should eventually occur provided that petroleum hydrocarbons are at sufficiently low levels in the intertidal zone. Management of harlequin duck populations could be accomplished through protection and possible enhancement of undisturbed riparian corridors within timber sale areas. Required width for protection of harlequin ducks using riparian corridors has not been determined conclusively. Nest locations in 1991 indicated that current buffer strips required for protection of anadromous fish streams may not protect all harlequin duck breeding habitat.
Harlequin ducks are among the least understood waterfowl species in North America. Prior to the 1990 feasibility study, which reported characteristics of streams on which harlequin duck broods were observed, little was known about habitat requirements of harlequin ducks breeding in Prince William Sound. The harlequin duck restoration crew began locating and recording harlequin duck nesting habitat in 1991.
The harlequin duck restoration project in 1992 will continue to document nesting and brood rearing habitat requirements of breeding harlequin ducks by capturing and radio tagging hens. Study of nest site habitat, including nest bowl (down lined depression containing eggs) cover, may provide information for habitat enhancement. By documenting breeding stream habitat within the structure of a hierarchical stream profile, a model predicting potential breeding habitat will be developed for use in the oil spill area and other coastal areas. A catalog of harlequin duck breeding streams in eastern Prince William Sound will be completed. Duckling survival and productivity will be determined by monitoring radio tagged hens throughout the brood rearing period. Molting habitat and population status will be determined using standardized boat survey methods developed in 1991.
Prince William Sound
Seabirds - Sea ducks
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Proposal: PDF Not Available
Funding Recommendations: View
Funding Detail For: 1992
Quarterly Project Tasks For: 1992
Annual Report: 1992: Not Applicable
Final Report: View
Publications from this Project: None Available