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ABSTRACT Conditions in Alaska, USA, pose a challenge for monitoring populations of Brachyramphus murrelets using standard survey methods, because of strong winds, 2 sympatric species, short nights, and variable nesting habitat. We tested 3 methods for monitoring Brachyramphus murrelets breeding in the Kodiak Archipelago, Alaska, in 2010-2012. In addition to standard audio-visual and radar methods, we tested-for the first time with murrelets in Alaska-the application of autonomous acoustic recorders for monitoring vocal activity. We completed 74 radar, 124 audio-visual, and 134 autonomous acoustic surveys, focused on presunrise activity peaks; this yielded 26,375 murrelet detections. Marbled ( B. marmoratus) and Kittlitz's murrelets ( B. brevirostris) could not be distinguished using combinations of radar and acoustic recordings; therefore, at-sea surveys will be required to determine localized species proportions. Of the 3 methods, radar sampled the largest area and detected silently flying murrelets, providing the most reliable data on local populations; however, radar identification of murrelets was unreliable in winds exceeding 18 km/hr. Audio-visual surveys were useful for species identification and to document behaviors associated with local nesting, whereas autonomous acoustic recorders allowed season-long monitoring of murrelet vocal activity. Within potential forest-nesting habitat of marbled murrelets, all 3 methods gave similar measures of presunrise murrelet activity, but only radar reliably sampled murrelets commuting between nest and ocean. Because of their low cost and flexible programming, automated sound recorders offer an affordable way to sample vocal activity prior to more intensive or expensive radar and audio-visual surveys. We recommend that population monitoring and habitat studies of Brachyramphus murrelets in Alaska include combinations of all 3 methods. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

ABSTRACT Autonomous sensors and automated analysis have great potential to reduce cost and increase efficacy of wildlife monitoring. By increasing sampling effort, autonomous sensors are powerful at detecting rare and elusive species such as the marbled murrelet ( Brachyramphus marmoratus). New approaches must be tested for comparability to existing methodologies, so we compared the results of inland audio-visual and of automated acoustic monitoring for marbled murrelets, conducted during the 2010 breeding season, at 7 sites in the Santa Cruz Mountains, California, USA. We found automated acoustic surveys and analysis had fewer detections per morning compared with audio-visual surveyors, but the rate of automated acoustic detections per morning was positively and strongly correlated with the rate of audio-visual detections per mornings ( r = 0.96, P < 0.01). Furthermore, acoustic monitoring sampled 10 times more mornings per site ( [ABSTRACT FROM AUTHOR]

ABSTRACT The Kittlitz's murrelet ( Brachyramphus brevirostris) is a small, dispersed-nesting seabird that often occurs in glacially influenced marine waters of Alaska and eastern Russia during the breeding season. Owing to its association with glacial habitats and apparent population declines in some parts of its range, the Kittlitz's murrelet has been the subject of considerable conservation concern in recent years. We present the first-ever estimates of breeding season and annual survival of the Kittlitz's murrelet. We estimated survival by capturing 914 murrelets and radiotagging 191 of them in Icy Bay, Alaska, 2007-2012. We used a multi-state mark-recapture framework to estimate breeding season survival. Daily survival probabilities were similar in the 3 spatial states (Icy Bay, Gulf of Alaska, nest; range = 0.996-0.999), resulting in an overall 60-day breeding season survival probability of 0.89 (SE = 0.04). The only apparent source of fatality of Kittlitz's murrelets during the breeding season was avian predators, specifically bald eagle ( Haliaeetus leucocephalus) and peregrine falcon ( Falco peregrinus). We estimated mean apparent annual survival across all years as 0.80 (SE = 0.33) with a recapture probability of 0.079 (SE = 0.032), resulting in a 305-day non-breeding season survival probability of 0.90 (SE = 0.37). We found that survival was lower than expected based on life-history theory and allometry, and that fatality risk was greater in the breeding season compared to other parts of the year. Our results indicating low survival rates of Kittlitz's murrelets are consistent with the observed decline of 10% per annum in the local population of this species in Icy Bay. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The article discusses findings of a study to quantify inland activity patterns and flight altitudes of Marbled Murrelets or Brachyramphus marmoratus in Northern California. It notes the threatened species status of the Marbled Murrelet and the effectiveness of using marine radar to measure passage rates and altitudes of murrelets. The research shows that 2,780 murrelets were detected flying towards land during 78 dawn surveys conducted in February to December 2012.

The article evaluates Kittlitz's Murrelet Brachyramphus brevirostris population trend for the initial time frame, from 1986 to 2012, for Prince William Sound, Alaska. It reveals that Prince William Sound had factors that would make the population estimates to be sensitive to misidentification of species. It offers evidence that misidentification took place, and re-analyzes the population trend censoring two years with suspected misidentification. It also explains that analyses made suggest no significant drop of Kittlitz's Murrelets in Prince William Sound.

The article presents a study on whether at-sea distributions of Marbled Murrelets BRachyramphus marmoratus on the southwest coast of Vancouver Island in British Columbia are spatially associated with Gray Whales Eschrichtius robustus. The researchers performed surveys of Marbled Murrelets and whales from a 10.6 meter passenger vessel along a 105 kilometer transect from Bamfield to Port Renfrew. They used the Pythagorean theorem to measure the distance to the nearest whale for every transect segment. They found that varying oceanic conditions may cause changes in the abundance and distribution of Marbled Murrelets.

The article presents a study on the habitat use and spatial distribution of Marbled Murrelets Brachyramphus marmoratus at Port Snettisham in Juneau, Alaska. The researchers used voice recorders to note the numbers of birds sitting on the water within 50 meters on either side of the boat as well as the observation times. They used the Classification and Regression Tree (CART) methods to analyze murrelet distribution with respect to habitat features. They found that Port Snettisham is important for murrelets because they occurred at higher densities than studies of other areas have found.

The article discusses a study of the distribution, abundance and trend estimates of the Kittlitz's Murrelet Brachyramphus brevirostris in Prince William Sound (PWS), Alaska from 1972 and 2007. A population model was developed for the study using the field estimates and variances for Marbled, Kittlitz's and unidentified murrelets. The populations of Brachyramphus murrelets were found to be declining based on field and model estimates. The possible role of a regional, contemporaneous alteration in the environment in the long-term decline of the two species is mentioned. Also emphasized is the need to include the Brachyramphus species in a list of conservation priorities.

The article presents study on the performative molt of Marbled Murrelet (Brachyramphus marmoratus). Study shows that juvenile murrelets may serve as a replacement of the juvenal contour feathers at sea following fledging. It notes that the plumage transition covers the uniform dark brown to black feathers on the upper part of the juveniles' body. This is attributed to the performative molt of at least the feathers of the neck, upper abdomen, chin, and breast. It points out that juveniles need to invest energy in their transition from camouflaged terrestrial juvenal plumage to counter-shaded formative plumage.

The article presents a study which examines the potential of Marbled Murrelet, a seabird, nest predation probability in the regions of southwestern British Columbia. It compares 488 simulated murrelet nests covering the sites with hard edges or recent clearcuts, soft edges or regenerating forests, and natural edges such riparian areas. The study reveals that managed forest landscapes provide risk to Marbles Murrelet nest predation. The results also indicates that dynamic fragmentation decreases as forests regenerate.

The article examines the abundance patterns of Kittlitz's Murrelet (KM), a rare, non-colonial seabird often associated with tidewater glaciers and a recent candidate for listing under the Endangered Species Act. The authors estimate the abundance of KMs across space and time from at-sea surveys along Alaska coast, and the use these data to develop spatial models to describe abundance patterns and identify environmental factors affecting abundance. Results of the study are discussed, and recommendations for monitoring KMs and other marine species are provided.

1. For the overwhelming majority of species, we lack long-term information on the dynamics of populations. As a consequence, we face considerable uncertainty about how to discriminate among competing hypotheses of population decline and design conservation plans. 2. The marbled murrelet Brachyramphus marmoratus is a small seabird that nests in coastal old-growth forest but feeds year-round in near-shore waters of the north-eastern Pacific. Although a decline in nesting habitat is the primary reason why marbled murrelets are listed as threatened in Canada, nest predation and food availability may also influence population abundance. To examine the hypothesis that murrelet populations are influenced by variation in diet quality, we analysed stable-carbon and -nitrogen isotopes in feathers of museum specimens collected in the Georgia Basin, British Columbia. 3. Between 1889 and 1996, we found a decline in stable isotopic signatures that was approximately equal to a 62% drop in trophic feeding level. We also found that the estimated proportion of fish in murrelet diet was related closely to murrelet abundance over the past 40 years, as estimated from volunteer surveys. Using these isotopic data, we modelled population size as a function of variation in reproductive rate due to changes in diet quality and found that our model matched closely the 40-year field estimates. We then applied our 107-year isotopic record to the model to back-cast estimates of population growth rate to 1889. 4. Our results suggest that, up to the 1950s, murrelet populations in the Georgia Basin were capable of growing and were probably limited by factors other than diet quality. After this period, however, our results imply that murrelets were often, but not solely, limited by diet quality. 5. Synthesis and applications. Protecting nesting habitat may not be sufficient to rebuild populations of this highly secretive and threatened seabird and recovery might also require the restoration of marine habitat quality, as well as a better understanding of how ocean climate affects prey abundance and reproductive rate. Combined with contemporary demographic data, stable isotope analysis of historic samples provides a unique opportunity to reconstruct population histories for species where we lack long-term information. [ABSTRACT FROM AUTHOR]

We estimated annual local survival rates for after-hatch-year (≥1-yr old) marbled murrelets (Brachyramphus marmoratus) in central California using Cormack­Jolly­Seber mark-recapture models and radiotelemetry, and we modeled the effect of oceanographic conditions, sex, and radiotagging. We captured 331 after-hatch-year murrelets from 1997 to 2003, of which 117 were radiotagged. Recapture rates were best modeled using a term that reflected differences in capture effort among sampling occasions (ρeffort) and ranged from 0.068 to 0.166. The most highly ranked model (ΦPDO+radio, ρeffort) indicated that survival rates were positively related to the strength of the Pacific Decadal Oscillation (PDO) and were negatively affected by radiotransmitters in the year following tagging. Mortality was relatively low in warm-water years, perhaps because murrelets flew inland to breed less frequently and were less exposed to avian predators. Two competing models indicated that survival in the year following tagging was affected by (1) only radiotagging (model Φradio, ρeffort), and (2) radiotagging and sex (model Φsex+radio, ρeffort). Model-averaged survival estimates were 0.868 (SE = 0.074) and 0.896 (SE = 0.067) for males and females, respectively, that were not radiotagged and 0.53 1 (SE = 0.175) and 0.572 (SE = 0.181) for males and females, respectively, that were radiotagged. Mortality of radiomarked individuals was greatest during a domoic acid (a neurotoxin in the marine environment) bloom in 1998 (Φ = 0.160–0.400) and radiomarking impacts were much less pronounced during typical years (Φ = 0.724–0.810). Additional causes of mortality included predation by peregrine falcons (Falco peregrinus) and oil spills. Survival for nonmarked individuals was similar or higher than what was estimated for murrelets in British Columbia and what was predicted for murrelets based on comparative analyses of other Alcid species, suggesting that mortality of after-hatch-year murrelets is not an immediate threat to population viability in the region. [ABSTRACT FROM AUTHOR]

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Interspecific hybridization can have importantconsequences for conservation, but can bedifficult to detect using morphologicalmarkers. To test the utility of nuclear intronsfor investigating hybridization and geneticintrogression, we analyzed variation in fivenuclear introns and the mitochondrialcytochrome b gene in two species ofseabirds that are declining and may behybridizing: marbled murrelets( Brachyramphus marmoratus) and Kittlitz'smurrelets ( B. brevirostris). No alleleswere shared between samples of the two species,and intron alleles formed reciprocallymonophyletic groups in gene trees. Our resultssuggest that few murrelets in Alaska are F1, F2or back-cross hybrids,and that gene pools of these species have beenindependent for 1.8 to 5.7 million years. Weconclude that introns are a potentially richsource of markers for analyzing hybridizationand introgression in endangered or decliningspecies. [ABSTRACT FROM AUTHOR]

Presents a documentation of Kittlitz's Murrelet (Brachyramphus brevirostris) vocalizations based on recordings made in Glacier Bay, Alaska in 1994. Study area; Comparison with Marbled Murrelet; Results.

The article focuses on a study that analyzed survey data as a part of the Symposium on Population Status and Trends of Kittlitz's Murrelet in Prince William Sound (PWS), Alaska, between 1989 and 2007. The study showed that Brachyramphus murrelets in PWS declined by about 68 percent between 1989 and 2007.