Micro mercury trapped ion clock prototypes with 10[Formula: see text] frequency stability in 1-liter packages.

Modern communication and navigation systems are increasingly relying on atomic clocks. As timing precision requirements increase, demands for lower SWaP (size, weight, and power) clocks rise. However, it has been challenging to break through the general trade-off trend between the clock stability performance and SWaP. Here we demonstrate micro mercury trapped ion clock (M2TIC) prototypes integrated with novel micro-fabricated technologies to simultaneously achieve high performance and low SWaP. The M2TIC prototypes could reach the [Formula: see text]-stability level in 1 day with a SWaP of 1.1 L, 1.2 kg, and under 6 W of power. This stability level is comparable to the widely used rack-mount Microchip 5071A cesium frequency standard. These standalone prototypes survived regular commercial shipping across the North American continent to a government laboratory, where their performance was independently tested. The M2TIC sets a new reference point for SWaP and performance and opens opportunities for high-performance clocks in terrestrial and space applications.

Population dynamics and resource availability drive seasonal shifts in the consumptive and competitive impacts of introduced house mice (Mus musculus) on an island ecosystem.

Background: House mice (Mus musculus) are widespread and invasive on many islands where they can have both direct and indirect impacts on native ecological communities. Given their opportunistic, omnivorous nature the consumptive and competitive impacts of house mice on islands have the potential to vary over time in concert with resource availability and mouse population dynamics. Methods: We examined the ecological niche of invasive house mice on Southeast Farallon Island, California, USA using a combination of mouse trapping, food resource surveys, and stable isotope analysis to better understand their trophic interactions with native flora and fauna. Specifically, we coupled the analysis of seasonal variation in resource availability over a 17-year period (2001-2017), carbon (δ 13C) and nitrogen (δ 15N) stable isotope values of mouse tissue and prey resources in a single year (2013), and isotopic niche and mixing models to quantify seasonal variation in mouse diets and the potential for resource overlap with native species. Results: We found that plants were the most important resource for house mice during the spring months when vegetation is abundant and mouse populations are low following heavy precipitation and declines in mouse abundance during the winter. While still consumed, plants declined in dietary importance throughout the summer and fall as mouse populations increased, and seabird and arthropod resources became relatively more available and consumed by house mice. Mouse abundance peaks and other resource availability are low on the island in the fall months when the isotopic niches of house mice and salamanders overlap significantly indicating the potential for competition, most likely for arthropod prey. Discussion: Our results indicate how seasonal shifts in both mouse abundance and resource availability are key factors that mediate the consumptive and competitive impacts of introduced house mice on this island ecosystem. As mice consume and/or compete with a wide range of native taxa, eradication has the potential to provide wide-reaching restoration benefits on Southeast Farallon Island. Post-eradication monitoring focused on plant, terrestrial invertebrate, salamander, and seabird populations will be crucial to confirm these predictions.

Discovery of novel fish papillomaviruses: From the Antarctic to the commercial fish market.

Fish papillomaviruses form a newly discovered group broadly recognized as the Secondpapillomavirinae subfamily. This study expands the documented genomes of the fish papillomaviruses from six to 16, including one from the Antarctic emerald notothen, seven from commercial market fishes, one from data mining of sea bream sequence data, and one from a western gull cloacal swab that is likely diet derived. The genomes of secondpapillomaviruses are ∼6 kilobasepairs (kb), which is substantially smaller than the ∼8 kb of terrestrial vertebrate papillomaviruses. Each genome encodes a clear homolog of the four canonical papillomavirus genes, E1, E2, L1, and L2. In addition, we identified open reading frames (ORFs) with short linear peptide motifs reminiscent of E6/E7 oncoproteins. Fish papillomaviruses are extremely diverse and phylogenetically distant from other papillomaviruses suggesting a model in which terrestrial vertebrate-infecting papillomaviruses arose after an evolutionary bottleneck event, possibly during the water-to-land transition.

Geolocator tagging links distributions in the non-breeding season to population genetic structure in a sentinel North Pacific seabird.

We tested the hypothesis that segregation in wintering areas is associated with population differentiation in a sentinel North Pacific seabird, the rhinoceros auklet (Cerorhinca monocerata). We collected tissue samples for genetic analyses on five breeding colonies in the western Pacific Ocean (Japan) and on 13 colonies in the eastern Pacific Ocean (California to Alaska), and deployed light-level geolocator tags on 12 eastern Pacific colonies to delineate wintering areas. Geolocator tags were deployed previously on one colony in Japan. There was strong genetic differentiation between populations in the eastern vs. western Pacific Ocean, likely due to two factors. First, glaciation over the North Pacific in the late Pleistocene might have forced a southward range shift that historically isolated the eastern and western populations. And second, deep-ocean habitat along the northern continental shelf appears to act as a barrier to movement; abundant on both sides of the North Pacific, the rhinoceros auklet is virtually absent as a breeder in the Aleutian Islands and Bering Sea, and no tagged birds crossed the North Pacific in the non-breeding season. While genetic differentiation was strongest between the eastern vs. western Pacific, there was also extensive differentiation within both regional groups. In pairwise comparisons among the eastern Pacific colonies, the standardized measure of genetic differentiation (FꞌST) was negatively correlated with the extent of spatial overlap in wintering areas. That result supports the hypothesis that segregation in the non-breeding season is linked to genetic structure. Philopatry and a neritic foraging habit probably also contribute to the structuring. Widely distributed, vulnerable to anthropogenic stressors, and exhibiting extensive genetic structure, the rhinoceros auklet is fully indicative of the scope of the conservation challenges posed by seabirds.

Killer whales redistribute white shark foraging pressure on seals.

Predatory behavior and top-down effects in marine ecosystems are well-described, however, intraguild interactions among co-occurring marine top predators remain less understood, but can have far reaching ecological implications. Killer whales and white sharks are prominent upper trophic level predators with highly-overlapping niches, yet their ecological interactions and subsequent effects have remained obscure. Using long-term electronic tagging and survey data we reveal rare and cryptic interactions between these predators at a shared foraging site, Southeast Farallon Island (SEFI). In multiple instances, brief visits from killer whales displaced white sharks from SEFI, disrupting shark feeding behavior for extended periods at this aggregation site. As a result, annual predations of pinnipeds by white sharks at SEFI were negatively correlated with close encounters with killer whales. Tagged white sharks relocated to other aggregation sites, creating detectable increases in white shark density at Ano Nuevo Island. This work highlights the importance of risk effects and intraguild relationships among top ocean predators and the value of long-term data sets revealing these consequential, albeit infrequent, ecological interactions.

Microbial Ecology of the Western Gull (Larus occidentalis).

Avian species host diverse communities of microorganisms which have important roles in the life of birds, including increased metabolism, protection from disease, and immune system development. Along with high human populations and a diversity of human uses of coastal zones, anthropogenic food sources are becoming increasingly available to some species, including gulls. Anthropogenic associations increase the likelihood of encountering foreign or pathogenic bacteria. Diseases in birds caused by bacteria are a substantial source of avian mortality; therefore, it is essential to characterize the microbiome of seabirds. Here, we determined both core and environmentally derived microbial communities of breeding western gulls (Larus occidentalis) from six colonies in California and Oregon. Using DNA extracted from bacterial swabs of the bill, cloaca, and feet of gulls, 16S rRNA gene sequencing was performed targeting the V4 region. We identified a total of 8542 operational taxonomic units (OTUs) from 75 gulls. Sixty-eight OTUs were identified in gulls from all six colonies with the greatest representation from phyla's of Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. Overall, microbial richness based on Chao's Abundance-based Coverage Estimator (ACE) index was similar for all colonies (mean = 2347 OTUs) with the smallest coastal colonies having the highest richness (mean = 2626 OTUs) and the largest colonies, located farther off-shore, having the lowest (mean = 2068 OTUs). This survey represents the most in-depth assessment to date of microbes associated with western gulls, and the first study to identify both species-specific and environmentally derived bacteria across multiple populations.

Genome Sequence of a Gyrovirus Associated with Ashy Storm-Petrel.

Ashy storm-petrels (order Procellariiformes) are seabirds that are found along the coast of California to Baja Mexico. A novel gyrovirus was identified from a cloacal swab of an ashy storm-petrel, which is the second gyrovirus to be identified in sea birds, the first being found in the related northern fulmar.

Increased reproductive investment associated with greater survival and longevity in Cassin's auklets.

Individuals increase lifetime reproductive output through a trade-off between investment in future survival and immediate reproductive success. This pattern may be obscured in certain higher quality individuals that possess greater reproductive potential. The Cassin's auklet (Ptychoramphus aleuticus) is a long-lived species where some individuals exhibit greater reproductive ability through a behaviour called double brooding. Here, we analyse 32 years of breeding histories from marked known-age auklets to test whether double brooding increases lifetime fitness despite the increased mortality and reduced lifespan higher reproductive effort would be expected to incur. Multistate mark-recapture modelling revealed that double brooding was strongly positively associated with higher annual survival and longevity. The mean (95% confidence interval) apparent survival was 0.69 (0.21, 0.91) for individuals that executed a single brood and 0.96 (0.84, 0.99) for those that double-brooded. Generalized linear mixed models indicated individuals that attempted multiple double broods over their lifetime were able to produce on average seven times as many chicks and live nearly 6 years longer than birds that never attempted a double brood. We found that high-quality individuals exhibited both increased reproductive effort and longevity, where heterogeneity in individual quality masked expected life-history trade-offs.

Population-level plasticity in foraging behavior of western gulls (Larus occidentalis).

BACKGROUND: Plasticity in foraging behavior among individuals, or across populations may reduce competition. As a generalist carnivore, western gulls (Larus occidentalis) consume a wide range of marine and terrestrial foods. However, the foraging patterns and habitat selection (ocean or land) of western gulls is not well understood, despite their ubiquity in coastal California. Here, we used GPS loggers to compare the foraging behavior and habitat use of western gulls breeding at two island colonies in central California. RESULTS: Gulls from offshore Southeast Farallon Island (SFI; n = 41 gulls) conducted more oceanic trips (n = 90) of shorter duration (3.8 ± 3.3 SD hours) and distance (27.1 ± 20.3 km) than trips to the mainland (n = 41) which were nearly 4 times longer and 2 times farther away. In contrast, gulls from coastal Año Nuevo Island (ANI; n = 20 gulls) foraged at sites on land more frequently (n = 103) but trip durations (3.6 ± 2.4 h) and distances (20.8 ± 9.4 km) did not differ significantly from oceanic trips (n = 42) where trip durations were only slightly shorter (2.9 ± 2.7 h) and equidistant (20.6 ± 12.1 km). Gulls from both colonies visited more sites while foraging at sea but spent significantly longer (3-5 times) durations at each site visited on land. Foraging at sea was also more random compared to foraging trips over land where gulls from both colonies visited the same sites on multiple trips. The total home range of gulls from SFI (14,230 km2) was 4.5 times larger than that of gulls from ANI, consistent with greater resource competition resulting from a larger abundance of seabirds at SFI. CONCLUSIONS: Population-level plasticity in foraging behavior was evident and dependent on habitat type. In addition, gulls from SFI were away foraging longer than gulls from ANI (22% vs. 7.5%, respectively), which impacts the defense of territories and attempts at nest predation by conspecifics. Our results can be used to explain lower chick productivity at SFI, and can provide insight into increased gull activity in urban areas.

Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.

Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution.

Shifting Effects of Ocean Conditions on Survival and Breeding Probability of a Long-Lived Seabird.

With a rapidly changing climate, there is an increasing need to predict how species will respond to changes in the physical environment. One approach is to use historic data to estimate the past influence of environmental variation on important demographic parameters and then use these relationships to project the abundance of a population or species under future climate scenarios. However, as novel climate conditions emerge, novel species responses may also appear. In some systems, environmental conditions beyond the range of those observed during the course of most long-term ecological studies are already evident. Yet little attention has been given to how these novel conditions may be influencing previously established environment-species relationships. Here, we model the relationships between ocean conditions and the demography of a long-lived seabird, Brandt's cormorant (Phalacrocorax penicillatusI), in central California and show that these relationships have changed in recent years. Beginning in 2007/2008, the response of Brandt's cormorant, an upper trophic level predator, to ocean conditions shifted, resulting in lower than predicted survival and breeding probability. Survival was generally less variable than breeding probability and was initially best predicted by the basin-scale forcing of the El Niño Southern Oscillation rather than local ocean conditions. The shifting response of Brandt's cormorant to ocean conditions may be just a proximate indication of altered dynamics in the food web and that important forage fish are not responding to the physical ocean environment as expected. These changing relationships have important implications for our ability to project the effects of future climate change for species and communities.

As the egg turns: monitoring egg attendance behavior in wild birds using novel data logging technology.

Egg turning is unique to birds and critical for embryonic development in most avian species. Technology that can measure changes in egg orientation and temperature at fine temporal scales (1 Hz) was neither readily available nor small enough to fit into artificial eggs until recently. Here we show the utility of novel miniature data loggers equipped with 3-axis (i.e., triaxial) accelerometers, magnetometers, and a temperature thermistor to study egg turning behavior in free-ranging birds. Artificial eggs containing egg loggers were deployed in the nests of three seabird species for 1-7 days of continuous monitoring. These species (1) turned their eggs more frequently (up to 6.5 turns h(-1)) than previously reported for other species, but angular changes were often small (1-10° most common), (2) displayed similar mean turning rates (ca. 2 turns h(-1)) despite major differences in reproductive ecology, and (3) demonstrated distinct diurnal cycling in egg temperatures that varied between 1.4 and 2.4 °C. These novel egg loggers revealed high-resolution, three-dimensional egg turning behavior heretofore never measured in wild birds. This new form of biotechnology has broad applicability for addressing fundamental questions in avian breeding ecology, life history, and development, and can be used as a tool to monitor birds that are sensitive to disturbance while breeding.

Timing is everything: flexible phenology and shifting selection in a colonial seabird.

1. In order to reproduce successfully in a temporally varying environment, iteroparous animals must exhibit considerable behavioural flexibility across their lifetimes. By adjusting timing of breeding each year, parents can ensure optimal overlap between the energy intensive period of offspring production and the seasonal peak in favourable environmental conditions, thereby increasing their chances of successfully rearing young. 2. Few studies investigate variation among individuals in how they respond to fluctuating conditions, or how selection acts on these individual differences, but this information is essential for understanding how populations will cope with rapid environmental change. 3. We explored inter-annual trends in breeding time and individual responses to environmental variability in common guillemots Uria aalge, an important marine top predator in the highly variable California Current System. Complex, nonlinear relationships between phenology and oceanic and climate variables were found at the population level. Using a novel application of a statistical technique called random regression, we showed that individual females responded in a nonlinear fashion to environmental variability, and that reaction norm shape differed among females. 4. The pattern and strength of selection varied substantially over a 34-year period, but in general, earlier laying was favoured. Females deviating significantly from the population mean laying date each year also suffered reduced breeding success, with the strength of nonlinear selection varying in relation to environmental conditions. 5. We discuss our results in the wider context of an emerging literature on the evolutionary ecology of individual-level plasticity in the wild. Better understanding of how species-specific factors and local habitat features affect the timing and success of breeding will improve our ability to predict how populations will respond to climate change.

Helminth community of scaled quail (Callipepla squamata) from western Texas.

Forty-eight scaled quail (Callipepla squamata) were collected during August 2002 at Elephant Mountain Wildlife Management Area in Brewster County, Texas, and examined for helminths. Eight species of helminths were found (5 nematodes and 3 cestodes), representing 2,811 individuals. Of these species, Gongylonema sp., Procyrnea pileata, and Choanotaenia infundibulum are reported from scaled quail for the first time. Prevalence of Aulonocephalus pennula, Gongylonema sp., Oxyspirura petrowi, Physaloptera sp., P. pileata, C. infundibulum, Fuhrmannetta sp., and Rhabdometra odiosa was 98, 2, 56, 4, 60, 2, 25, and 35%, respectively. Aulonocephalus pennula numerically dominated, accounting for 88% of total worms. Statistical analyses were performed on the 5 species with > or = 25% prevalence using the after-hatch-year host sample (n = 38). Prevalence of P. pileata was higher (P = 0.049) in females than in males and higher (P = 0.037) in the sample collected from the site that had spreader dams (berms 1-2 m high and 4-55 m long constructed in varying sizes to catch and retain rainfall) than the control site (no spreader dams). Higher rank mean abundance of A. pennula and O. petrowi (P = 0.0001 and P = 0.0052, respectively) was found in the host sample collected from the site that had spreader dams than the control site. A host gender-by-collection site interaction (P = 0.0215) was observed for P. pileata. Findings indicate that scaled quail are acquiring indirect life cycle helminths in arid western Texas habitats.