Persistent Summer Mortalities of Common Murres along the Oregon Central Coast

Bayer, Range D.; Lowe, Roy W.; Loeffel, Robert

doi:10.2307/1368183

Cited by 11 publications

(7 citation statements)

References 18 publications

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“…Body mass reflects energy reserves, or fasting endurance (Hatch 1983), although no significant relationship has been found between fledging mass of murres and the probability of being resighted at the colony in future years (Hedgren 1981, Harris et al 1992). Conversely, attaining an adequate body mass before independence from parents at sea (Bayer et al 1991) and the onset of winter (Harris et al 1992) appears to be critical. Growth rates are higher at sea than at the colony (Birkhead 1977, Varoujean et al 1979) and, thus, moving to the sea might be the most efficient way to accelerate growth rates when provisioning rates are limited.…”

Section: Discussionmentioning

confidence: 99%

Consequences of foraging trip duration on provisioning behaviour and fledging condition of common murres Uria aalgae

Davoren

Montevecchi²

2003

Journal of Avian Biology

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We examine the provisioning constraints of a pursuit‐diving seabird in a cold ocean regime by comparing the behaviour of common murres Uria aalge rearing chicks at two colonies in the Northwest Atlantic during 1998‐2000. Funk Island is the largest (340,000–400,000 breeding pairs) and most offshore (60 km) colony of common murres in eastern Canada. Seventy‐five percent of the Northwest Atlantic population of common murres breeds on this island. Great Island is one island within the Witless Bay Ecological Reserve, which is the second largest breeding aggregation (100 000 breeding pairs) and is located near‐shore (2 km). The primary forage fish species in Newfoundland waters is capelin Mallotus villosus, which spawns on or near coastal beaches during summer. Therefore, the two study colonies differ in their distance to food resources and colony size. It is within this natural context that we compare: (1) prey types and frequency of delivery (amount of prey), (2) parental time budgets, and (3) the mass and condition (mass/wing length) of fledglings at both colonies. Similarly sized female capelin (100–150 mm) were delivered to chicks at both colonies. Foraging time per day per parent, a proxy of foraging effort, was similar at both colonies (Great Island: 5.1 h; Funk Island: 5.5 h), as was the percentage of time spent with mates (Great Island: 12.3%; Funk Island: 10.9%). Foraging trips, however, were longer at Funk Island (4.1 h) than at Great Island (2.9 h). This resulted in lower feeding rates of chicks (0.17 feeds per h) and poorer condition of fledglings (2.9 g/mm) at Funk Island compared to those at Great Island (0.22 feeds per h; 3.9 g/mm). We hypothesize that provisioning efforts are constrained at Funk Island by (1) distant food resources and increased competitor density, resulting in longer foraging trip durations and (2) the time spent paired with mates at the colony, which may reflect a minimum time required to maintain breeding sites due to higher breeding densities at Funk Island compared to Great Island. Demographic consequences of this poor fledgling condition at Funk Island are unknown, but fledglings may sufficiently accelerate growth at sea due to their closer proximity to an important nursery area. If fledgling survival is compromised, however, the lower potential for growth at Funk Island will impact the entire Northwest Atlantic population of common murres.

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Section: Discussionmentioning

confidence: 99%

Consequences of foraging trip duration on provisioning behaviour and fledging condition of common murres Uria aalgae

Davoren

Montevecchi²

2003

Journal of Avian Biology

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“…. Reduced breeding success during severe El Niiio events in 1982-83 and 1992-93 occurred widely at murre colonies in California, Oregon, Washington, and British Columbia ; ; Bayer et al 1991;Wilson 1991;Carter et al 2001). Severe El Nino events apparently resulted in poor prey conditions, which greatly impacted the proportion of adults that breed and breeding conditions for adults that laid eggs.…”

Section: Breeding Successmentioning

confidence: 99%

“…Survival rates of juveniles from the time of colony departure to breeding age varied from 17 to 41 % in 10 European studies, based mainly on band recoveries. Many hatching-year juveniles die between colony departure and during their first autumn (Birkhead 1974;Stenzel et al 1988;Bayer et al 1991 ). At the Isle of May, Scotland, survival of post-fledging murres decreased with later hatching date in 2 of 6 years studied (Harris et al 1992).…”

Section: Demography Adult and Subadult Survivalmentioning

confidence: 99%

Biology and conservation of the common murre in California, Oregon, Washington, and British Columbia / editors, David A. Manuwal ... [et al.].

Manuwal¹

2001

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Methods 3 Overview of the biology of the common murre 4 Reproductive ecology 5 Breeding habitat 5 Seasonal and daily colony attendance patterns 5 Timing of breeding 7 Egg laying 7 Incubation and hatching 8 Chick rearing and colony departure 8 Demography Adult and subadult survival Proportion of adults that breed Hatching success Fledging success Breeding success At-sea chick rearing Philopatry, recruitment, and intercolony movements Colony formation and irregular attendance Predators Foraging ecology Diet At-sea distributions California Oregon Washington British Columbia Movements Acknowledgments Literature cited Additional references Unpublished data and personal communications Chapter 2. Population trends of the common murre (Uria aalge califomica

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“…d This value is half way between the 33% value at age 4 and full recruitment at age 6 reported in Hudson (1985) for Skomer Island murres. ' That survival of young murres at sea is highly variable is demonstrated by a study on beached Oregon murres by Bayer et al (1991). The survival estimate is based on survival of banded birds to adulthood on the Helgoland Island (Mead, 1974) and Skomer Island (Birkhead and Hudson, 1977) murre populations along with juvenile survival estimates given above. '…”

Section: Brief Model Descriptionmentioning

confidence: 99%

Resource modeling moves into the courtroom

Swartzman

1996

Ecological Modelling

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In this paper I discuss the use of a population dynamics model to predict the future population size of colonial seabirds after damages from a loss due to oiling. Although simple, the model was developed in a litigation context by a retained 'team of experts' and presented some challenges both in communication of results and concept to environmental lawyers and in the interpretation of results in terms of the legal issues at hand. Use of models like these involve an adversarial relationship between scientists and modelers on each side of the case. Success in these cases arises not so much from scientific credibility or credentials of the scientists as from their ability to interpret their idiom in both intuitive and common sense fashion. Given the litiginous nature of environmental issues in our country and abroad, we are likely to be more involved in such issues in the future. I conclude with suggestions on how we might effectively approach problem resolution in this context.

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Persistent Summer Mortalities of Common Murres along the Oregon Central Coast

Cited by 11 publications

References 18 publications

Consequences of foraging trip duration on provisioning behaviour and fledging condition of common murres Uria aalgae

Consequences of foraging trip duration on provisioning behaviour and fledging condition of common murres Uria aalgae

Biology and conservation of the common murre in California, Oregon, Washington, and British Columbia / editors, David A. Manuwal ... [et al.].

Resource modeling moves into the courtroom

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