Foraging-Related Activity of Bald Eagles at a Washington Seabird Colony and Seal Rookery

  title={Foraging-Related Activity of Bald Eagles at a Washington Seabird Colony and Seal Rookery},
  author={James L. Hayward and Joseph G. Galusha and Shandelle M. Henson},
Abstract From 1980 to 1998, Washington's Bald Eagle (Haliaeetus leucocephalus) population increased at an annual rate of 10%. Over the same time period, foraging activity of Bald Eagles at marine bird breeding colonies also increased. From 1993 to 2008, we observed foraging-related behavior of Bald Eagles on Violet Point, Protection Island. This island hosts more than 70% of the breeding seabirds in Washington's inner seaways and serves as an important rookery for harbor seals (Phoca vitulina… 

Predator–prey dynamics of bald eagles and glaucous‐winged gulls at Protection Island, Washington, USA

The results suggest that the effects of bald eagle activity on the dynamics of a large gull colony were explained by a predator–prey relationship that included the possibility of coexistence but also the possible of gull colony extinction.

Migration and Winter Habitat Use of Glaucous-Winged Gulls (Larus glaucescens) from Triangle Island, British Columbia

Abstract. Understanding the movements and habitat use of marine birds is essential to inform conservation and marine spatial planning. Here, satellite transmitters were used to study the migration

Bald Eagle Predation on Sitka Black-Tailed Deer Fawns

  • S. Gilbert
  • Environmental Science
    Northwestern Naturalist
  • 2016
Bald Eagles (Haliaeetus leucocephalus) are known predators, but records of predation on large mammals are limited and highly seasonal. During winter, Bald Eagles are known to scavenge but not predate

Bald Eagle Predation on Double-Crested Cormorant and Herring Gull Eggs

Repeated Double-crested Cormorant (P. auritus) and Herring Gull egg predation events by Bald Eagles on a Double- cormorant–Herred Gull rookery in Rainy Lake along the U.S.–Canada border between Voyageurs National Park (VNP), MN, and Ontario, Canada is reported.

Density-Dependence in the Survival and Reproduction of Bald Eagles: Linkages to Chum Salmon

It is suggested that eagle populations in the Pacific Northwest are currently partially limited by density on the breeding grounds and partially by adult mortality in late winter, likely due to reduced late winter salmon stocks forcing eagles to exploit more marginal prey supplies.

Negative Interspecies Interactions in a Glaucous-Winged Gull Colony on Protection Island, Washington

Together, the tall grass and eagle predation appear to be carrying out a pincer movement which may be forcing the gulls into suboptimal nesting habitat and driving the decline of the gull colony on Protection Island.

Fitting in with the crowd: the role of prospecting in seabird behavioural trends

Although prospectors typically spent more time on the colony surface than adults, prospectors rarely socialized with conspecifics during their visits to the colony, possibly due to the absence of a citrus-like feather odour used in olfactory communication.

Unintended consequences: how the recovery of sea eagle Haliaeetus spp. populations in the northern hemisphere is affecting seabirds

Adult seabirds experience predation by many species, and many are taken on land by avian predators, including Giant Petrels Macronectes spp.

Modeling climate change impacts on overwintering bald eagles

Future climate-driven declines in winter food availability, coupled with a growing bald eagle population, may force eagles to seek alternate prey in the Puget Sound area or in more remote ecosystems.

Daily and Annual Habitat Use and Habitat-To-Habitat Movement By Glaucous-Winged Gulls At Protection Island, Washington

Abstract Central questions of ecology concern how and why organisms distribute themselves in time and space. Answers to these questions contribute to our understanding of the fitness of organisms and



Seasonal Timing of Bald Eagle Attendance and Influence on Activity Budgets of Glaucous-winged Gulls in Barkley Sound, British Columbia

Investigation of changes in Bald Eagle abundance in relation to gull breeding phenology over 6 years at Seabird Rocks and compare activity budgets of gulls shows that Bald Eagle attendance patterns at gull colonies coincide with hatching of gull chicks and can influence time-activity budgets ofulls, suggesting Predator-induced changes in gull behavior during the breeding season may influence reproductive success.

Factors Influencing Great Blue Heron Nesting Productivity on the Pacific Coast of Canada from 1998 to 1999

Abstract Surveys were conducted at 35 Great Blue Heron (Ardea herodias) colonies in urban and rural landscapes of south-coastal British Columbia, Canada, to investigate low nesting productivity


Dietary preferences of bald eagles reflect local prey availability in many parts of the United States; depending on time and place, eagles prey upon fish, marine birds, gull eggs, and sea otter pups and they scavenge cow, sheep, deer, salmon, and seal carcasses.

Rhinoceros Auklet (Cerorhinca monocerata) Burrow Counts, Burrow Density, Occupancy Rates, and Associated Habitat Variables on Protection Island, Washington: 2008 Research Progress Report

Unlike many species of seabirds that use the Salish Sea (Puget Sound, Georgia Basin and Strait of Juan de Fuca) during migration or for over-wintering, rhinoceros auklets (Cerorhinca monocerata)

Breeding Biology of the Rhinoceros Auklet in Washington

Investigation of the breeding biology of the Rhinoceros Auklet at three main colony sites on the coast of Washington found that early-hatched young grew more rapidly than chicks hatched at a later date and breeding success was higher on the inland colony sites.


To explore the contribution of eagles to the observed population decline of the Common Murre, a wide range of plausible models of murre demography are developed, finding that the match between the projected and observed murre numbers is generally much improved by the inclusion of eagle effects.

Influence of group size and habitat type on reproductive success in Common Murres (Uria aalge)

As a function of size, nesting colonies dilute the risk of predation and also may provide members with early warning of predator presence, and whether colonial nesting confers advantages on the adults, with respect to predation, depends on the numerical response of predators to colony size and location.

Historical Changes in the Physical and Vegetational Characteristics of Protection Island, Washington

Protection Island National Wildlife Refuge, WA, is home to the majority of breeding seabirds and harbor seals found in the Puget Sound/San Juan Island area. The island consists of a high central

Population trends of nesting Glaucous-winged Gulls, Larus glaucescens, in the southern Strait of Georgia, British Columbia

Between 1986 and 1999, the number of nesting Glaucous-winged Gulls (Larus glaucescens) at fourteen breeding colonies declined by 31% (1610 nests) in the southern Strait of Georgia, British Columbia.

Assessing bias in studies of bald eagle food habits

Bias associated with pellet analysis, food remains analysis, and direct observation are examined in the study of food habits of nonbreeding bald eagles on the northern Chesapeake Bay.