Mortality of Common Eider, &lt;em&gt;Somateria mollissima&lt;/em&gt; (Linnaeus, 1758), and other water birds during two inshore oiling events in southeastern Newfoundland, 2005 and 2006

Robertson, Gregory J.; Gilliland, Scott G.; Ryan, Pierre C.; Dussureault, Johanne; Power, Kyran; Turner, Bruce

doi:10.22621/cfn.v128i3.1601

Cited by 3 publications

(3 citation statements)

References 11 publications

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“…CountEm can be applied in any situation where large aggregations of animals can be captured in imagery. Its applications allow for estimating colony size, and CountEm can be particularly useful when an unbiased estimate of animals is needed rapidly to respond to an environmental emergency such as an oil spill (see Robertson et al, 2014).…”

Section: Acknowledgmentsmentioning

confidence: 99%

Multi‐image flock size estimation with CountEm: A case study with half a million Common Eiders and Greater Snow Geese

et al. 2022

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Many of the methods used for estimating population size from ecological surveys have limitations on precision, cost, and/or applicability. The CountEm method was proposed recently for estimating the number of individuals in large groups from single images. It is simple and efficient, and can be applied to any species. Here we present a case study by applying CountEm to a real ecological survey with 278 images of Greater Snow Geese (Anser caerulescens atlanticus) and Common Eiders (Somateria mollissima) flocks taken from fixed-wing aircraft in Eastern Canada. First, we evaluated the precision and counting time of CountEm on single images. Second, we developed and tested a new multi-image version of the CountEm software. We show that flock sizes of N > 35,000 can be estimated on single images in $5 min, from counting a sample of $200 birds, yielding relative SEs in the 5%À10% range. Processing times increased to 10-20 min when simultaneously processing large numbers of images that contained over half a million birds with only modest increases in relative SE (range: 10%À15%). Our results suggest that CountEm may be used to save time and resources if incorporated into monitoring programs that utilize imagery in the abundance estimates.

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Section: Acknowledgmentsmentioning

confidence: 99%

Multi‐image flock size estimation with CountEm: A case study with half a million Common Eiders and Greater Snow Geese

et al. 2022

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“…Jenssen and Ekker (1991) found that metabolic heat production of common eiders (Somateria mollissima) resting in 5.5 o C water for three hours after external application of 10 to 70 mL of crude oil increased over time and with dose, and that there was no change in metabolic rate at the low dose of 2.5 ml. Eiders are a large, wellinsulated northern bird and any impacts of oiling found in eiders likely would be as bad or worse in other smaller, or less insulated seabirds (Robertson et al 2014). Adelie Penguins (Pygoscelis D r a f t adeliae) with residual vegetable oil on their plumage had metabolic rates 50% higher than control birds, and the authors hypothesized that exposure to oil could lead to mass losses of penguins (Culik et al 1991).…”

Section: Metabolic Ratementioning

confidence: 99%

Offshore oil and gas, and operational sheen occurrence: is there potential harm to marine birds?

Morandin¹,

O’Hara

2016

Environ. Rev.

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Hydrocarbon discharges into the ocean, both regulated and accidental, occur from offshore drilling and production operations, and can result in oil sheen (≤3 μm thick) and slick (>3 μm thick) formation, potentially harming marine birds. Sheens may commonly occur around offshore oil and gas platforms in Atlantic Canada, however, there is little information on regularity of occurrence. Further, there are few direct studies on potential impacts of sheens, associated with offshore oil and gas operations, on marine birds. We reviewed potential sources and frequency of hydrocarbon accumulation on sea surfaces from offshore oil and gas operations in Atlantic Canada, and the likelihood of overlap with marine birds. We conducted a literature review on lethal and sub-lethal effects of low levels of oil contact and ingestion on marine birds, focusing on studies that describe measured dosages of oil. We extrapolated from these data on low-dose oil exposure to link possible effects to marine birds resulting from exposure to sheens. We found that sheens occur around production operations in Atlantic Canada at allowable levels of oil concentrations in produced water. Frequency and extent of occurrence cannot be estimated from current monitoring practices. While immediate lethal effects to seabirds likely are not common from external oiling of feathers from sheens, added stressors, such as cold weather, can result in external oiling from sheens having significant impact on seabird metabolic rate and can be ultimately lethal. Ingestion of small amounts of oil, doses that realistically could be expected from exposure to sheens, in some cases resulted in sub-lethal effects to adult seabirds, primarily affecting metabolic rate, sub-lethal health impacts, and reproductive output. Nestlings and eggs do not come in direct contact with sheens, yet these life stages are highly sensitive to oil, and transfer of oil from adults exposed to sheens likely is above tolerance levels at times. Negative effects to reproductive output from small doses of ingested oil could be causing undetected impacts on marine birds and marine bird populations. Lack of standardized monitoring of marine bird contact with sheens and potential harm makes assessments of magnitude and extent of impact problematic.

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“…Moreover, common eiders are gregarious during brood‐rearing (Bédard and Munro ), molting, and migration and in the winter, often forming flocks of thousands of birds (Merkel , Milton et al ). Consequently, eider populations are particularly susceptible to environmental stressors that increase mortality at their breeding colonies and during winter (e.g., harvest, disease, predation, oil spills, pollution; Goudie et al , Robertson et al ).…”

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Sex-specific survival of adult common eiders in Nova Scotia, Canada

Milton¹,

Iverson

Smith

et al. 2016

Jour. Wild. Mgmt.

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Common eiders (Somateria mollissima) are large sea ducks with a circumpolar distribution and have high cultural significance to sport hunters and indigenous peoples in many countries. Their gregarious habits, including colonial breeding and forming large flocks during migration and winter, make eiders susceptible to environmental stressors during breeding and non-breeding seasons. Our objective was to assess whether low adult survivorship could be contributing to suspected local population declines in Nova Scotia, Canada. We banded molting male and breeding female common eiders along the marine coastline of Nova Scotia and recaptured them in later years. We found that from 1997 to 2011, when males and females were banded, male survival (S) was high (S ¼ 0.92; 95% CI ¼ 0.87-0.95), whereas female survival was approximately 10% lower (S ¼ 0.83; 95% CI ¼ 0.78-0.87) and at a level comparable to what has been reported in other regions of the world where eider populations are thought to be in decline. Recovery rates (f) of harvested male and female eiders were indistinguishable (f ¼ 0.013; 95% CI ¼ 0.010-0.016), suggesting that lower female survival is attributable to factors other than hunting. Supplementary analyses using a longer-term data set for females only and including live recapture data indicated that female survival rates have not changed markedly during the past 40 years and that the emigration rate from colonies is low ($6%). We conclude that to successfully conserve this population, sources of non-harvest female mortality should be investigated and used to develop targeted management solutions. We speculate that one of those sources of mortality is predation on females at breeding colonies, notably from eagles and mustelids.

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Mortality of Common Eider, <em>Somateria mollissima</em> (Linnaeus, 1758), and other water birds during two inshore oiling events in southeastern Newfoundland, 2005 and 2006

Cited by 3 publications

References 11 publications

Multi‐image flock size estimation with CountEm: A case study with half a million Common Eiders and Greater Snow Geese

Multi‐image flock size estimation with CountEm: A case study with half a million Common Eiders and Greater Snow Geese

Offshore oil and gas, and operational sheen occurrence: is there potential harm to marine birds?

Sex-specific survival of adult common eiders in Nova Scotia, Canada

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