About 62,000 dead or dying common murres (Uria aalge), the trophically dominant fish-eating seabird of the North Pacific, washed ashore between summer 2015 and spring 2016 on beaches from California to Alaska. Most birds were severely emaciated and, so far, no evidence for anything other than starvation was found to explain this mass mortality. Threequarters of murres were found in the Gulf of Alaska and the remainder along the West Coast. Studies show that only a fraction of birds that die at sea typically wash ashore, and we estimate that total mortality approached 1 million birds. About two-thirds of murres killed were adults, a substantial blow to breeding populations. Additionally, 22 complete reproductive failures were observed at multiple colonies region-wide during (2015) and after (2016-2017) the mass mortality event. Die-offs and breeding failures occur sporadically in murres, but the magnitude, duration and spatial extent of this die-off, associated with multi-colony and multi-year reproductive failures, is unprecedented and astonishing. These events cooccurred with the most powerful marine heatwave on record that persisted through 2014-2016 and created an enormous volume of ocean water (the "Blob") from California to Alaska with temperatures that exceeded average by 2-3 standard deviations. Other studies PLOS ONE | https://doi.org/10.1371/journal.pone.0226087 January 15, 2020 1 / 32 OPEN ACCESS Citation: Piatt JF, Parrish JK, Renner HM, Schoen SK, Jones TT, Arimitsu ML, et al. (2020) Extreme mortality and reproductive failure of common murres resulting from the northeast Pacific marine heatwave of 2014-2016. PLoS ONE 15(1):indicate that this prolonged heatwave reduced phytoplankton biomass and restructured zooplankton communities in favor of lower-calorie species, while it simultaneously increased metabolically driven food demands of ectothermic forage fish. In response, forage fish quality and quantity diminished. Similarly, large ectothermic groundfish were thought to have increased their demand for forage fish, resulting in greater top-predator demands for diminished forage fish resources. We hypothesize that these bottom-up and top-down forces created an "ectothermic vise" on forage species leading to their system-wide scarcity and resulting in mass mortality of murres and many other fish, bird and mammal species in the region during 2014-2017.

populations était aussi très sensible aux variations unitaires ou proportionnelles du succès d'éclosion moyen et des taux de survie des canetons ou des juvéniles. Étant donné les faibles effectifs d'échantillons disponibles pour certains aspects-clé du cycle de vie du Petit Fuligule, nous recommandons que des travaux additionnels soient effectués sur les taux vitaux qui ont une influence majeure sur l'accroissement des populations et leur effectif (ex. taux de survie des adultes). Nos modèles de cycle de vie devraient être testés et mis à jour régulièrement afin de guider l'étude et la gestion des populations de Petit Fuligule dans un contexte adaptatif.

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Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities.

Over the last 20 years scaup numbers have declined, and these declines have been greatest in the northern boreal forests of Canada and Alaska where most lesser scaup (Aythya affinis) nest. We studied nest success and duckling survival of lesser scaup over 3 field seasons, 2001–2003, on the Yukon Flats National Wildlife Refuge in northeastern Alaska, USA. Daily survival rate (DSR) of nests on our study area across all 3 years was 0.943 (n = 177 nests, 95% CI: 0.930–0.954), corresponding to a nest success of only 12.3%, considerably lower than published estimates of an average nest success as high as 57% for lesser scaup in the northern boreal forest. With Mayfield logistic regression, we investigated effects on nest survival of year, clutch initiation date, and nesting habitat type (large wetlands >10 ha, small wetlands <10 ha, and wooded creeks). Neither year nor clutch initiation date influenced nest survival; however, the odds of nest success on large wetlands was 49% lower than on wooded creeks (odds ratio = 0.512, 95% CI = 0.286, 0.918). Based on the model that used only habitat type for estimation, DSR on large wetlands was 0.931 (corresponding nest success = 7.6%), DSR on small wetlands was 0.941 (nest success = 11.1%), and DSR on wooded creeks was 0.963 (nest success = 26.2%). To estimate duckling survival, we monitored 10 broods (n = 75 ducklings) over 3 field seasons by radiotagging hens at nest hatch. Most duckling mortality (94%) occurred in the first 10 days after hatch. Average duckling survival during 1–10 days was 0.321 (95% CI: 0.122–0.772), during 11–20 days was 0.996 (95% CI: 0.891–1.040), and during 21–30 days was 0.923 (95% CI: 0.769–1.041). Three of 10 hens moved all or part of their broods overland between nesting and brood‐rearing wetlands for distances of 0.3–1.6 km. Our estimates of lesser scaup nest success and duckling survival on the Yukon Flats were among the lowest ever reported for ducks nesting at northern latitudes, even though the study site was in pristine boreal forest. Estimating and comparing scaup demographic rates from different geographic areas can contribute to improved conservation. Given the scarcity of information on scaup nesting in the boreal forest, basic nesting parameters are important to those trying to model scaup population dynamics.

Resumen. examinamos la ecología de nidificación de Euphagus carolinus a través del monitoreo de 162 nidos para obtener datos de supervivencia de nidos en alaska y de 252 registros adicionales de alaska y canadá para identificar habitats importantes para la nidificación y evaluar si las bajas tasas de éxito de nidos contribuyeron a las disminuciones poblacionales en alaska. en la costa de alaska y a lo largo de canadá, los nidos se encontraron principalmente en coníferas (85% de 212 nidos). todos los nidos en coníferas de alaska y el 80% de los de canadá estuvieron ubicados en ejemplares de Picea spp., principalmente P. mariana. en alaska se identificó un uso selectivo de ejemplares pequeños de Picea (<8 cm dap), resultando en un alto éxito reproductivo-la supervivencia de los nidos incrementó con la densidad de P. mariana, y el éxito de nidos en ejemplares de Picea (79%) fue mayor que el de los nidos ubicados en vegetación decidua (52%). la supervivencia de nidos en ejemplares más altos de Picea disminuyó, posiblemente debido a la depredación por parte de Tamiasciurus hudsonicus. los individuos de E. carolinus nidificaron cerca del agua en el interior (x _ = 8 m) y en el sur centro de alaska (x _ = 30 m), y los ejemplares pequeños de Picea parecieron ser importantes dentro de la mayor parte del área de distribución de la especie. Sin embargo, en el interior de alaska, la mayoría de los nidos se ubicaron en ejemplares de Salix (78%), los que dominaban la vegetación cercana al agua. el éxito de nidos en alaska promedió el 56%, similar a las tasas del mismo periodo en nueva inglaterra pero mayor que las de otras especies de Euphagus de américa del norte. Son necesarios estudios para verificar si la supervivencia de nidos es alta también en canadá y para investigar dónde y cómo el déficit en la supervivencia de adultos o juveniles puede estar limitando el crecimiento poblacional.neSting ecology of the RuSty BlackBiRd in alaSka and canada ecología de nidificación de Euphagus carolinus en alaska y canadá Abstract. we examined the nesting ecology of the Rusty Blackbird (Euphagus carolinus) from 162 nests monitored for nest survival in alaska and 252 incidental records from alaska and canada to identify important habitats for nesting and to test whether low rates of nest success are contributing to populations declines in alaska. in coastal alaska and throughout canada, nests were primarily in conifers (85% of 212 nests). all conifer nests in alaska and 80% of those in canada were placed in spruce (Picea spp.), primarily black spruce (P. mariana). in alaska use of small spruces (<8 cm dbh) was selective and resulted in high reproductive success-nest survival increased with black spruce density, and success of nests in spruce (79%) was higher than that of nests in deciduous vegetation (52%). Survival of nests in taller spruce declined, possibly from predation by red squirrels (Tamiasciurus hudsonicus). Rusty Blackbirds nested near water in interior (x _ = 8 m) and south-central alaska (x _ = 30 m), and small spruces near ...

ABSTRACT:Paralytic shellfish poisoning (PSP) is an acute toxic illness in humans resulting from ingestion of shellfish contaminated with a suite of neurotoxins (saxitoxins) produced by marine dinoflagellates, most commonly in the genus Alexandrium. Poisoning also has been sporadically suspected and, less often, documented in marine wildlife, often in association with an outbreak in humans. Kittlitz's Murrelet (Brachyramphus brevirostris) is a small, rare seabird of the Northern Pacific with a declining population. From 2008 to 2012, as part of a breeding ecology study, multiple Kittlitz's Murrelet nests on Kodiak Island, Alaska, were monitored by remote cameras. During the 2011 and 2012 breeding seasons, nestlings from several sites died during mild weather conditions. Remote camera observations revealed that the nestlings died shortly after consuming sand lance (Ammodytes hexapterus), a fish species known to biomagnify saxitoxin. High levels of saxitoxin were subsequently documented in crop content in 87% of nestling carcasses. Marine bird deaths from PSP may be underreported.

Little is known about the breeding ecology of Kittlitz's Murrelets (Brachyramphus brevirostris), a species suspected to have experienced both local and regional population declines in recent years. We studied aspects of their breeding ecology on Kodiak Island, Alaska, to better understand this poorly described member of the family Alcidae. We found 53 nests of Kittlitz's Murrelets during our study (2008–2011) and placed nest cameras at 33 nests to collect data on parental nest attendance, nestling provisioning, and nest survival. Incubation shift exchanges by adults generally occurs either prior to sunrise or after sunset. Adults brooded nestlings for just one day after hatching and did not attend nests thereafter except during provisioning visits. Adults provisioned nestlings an average of 107 times during nestling periods, with a single fish delivered during each visit. Pacific sand lance (Ammodytes hexapterus), a high‐lipid forage fish, accounted for 92% of fish delivered to nestlings. Nestlings grew rapidly, with a logistic growth rate constant (K) of 0.291, the highest rate yet documented among semiprecocial alcids. Young fledged an average of 25 d after hatching, when their body mass had reached an asymptote of 135.5 g, or 57% of adult body mass. Age at fledging and asymptotic nestling body mass (percent of adult mass) were low compared to other semiprecocial alcids. The mean number of young fledged per nest was 0.093, with 47% of nests predated, and nestlings dying prior to fledging at 21% of nests. The low number of parental provisioning visits, rapid nestling growth rates, and short nestling periods are consistent with adaptations to reduce the likelihood of nest predation and the energy expended by parents. The risk of nest predation and high energetic cost of breeding may make the reproductive success of Kittlitz's Murrelets more sensitive to declines in the availability and quality of their prey than most other alcids.