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Breeding within the Salish Sea by Pelagic Cormorant (Phalacrocorax pelagicus), Double-crested Cormorant (P. auritus) and Brandt's Cormorant (P. penicillatus) was summarized from published and unpublished sources for the 1891–1955 period. None of the 3 cormorant species were recorded breeding in the Salish Sea between 1792 and 1891 although sporadic breeding may have been missed. Pelagic Cormorants were first reported breeding at Mandarte Island, British Columbia, in 1891 and afterwards bred there regularly; by 1955, 22 colonies had formed in the central and northern Salish Sea, including the San Juan Islands (n = 9), Gulf Islands (n = 5), inner Strait of Juan de Fuca (n = 4), and northern Strait of Georgia (n = 4). Before regular breeding by Double-crested Cormorants began at Mandarte Island (1927) and Ballingall Islets (1934), they apparently bred sporadically at St. John's Point (Hornby Island) in the northern Salish Sea (1896) and Mandarte Island (1900). By 1955, 8 colonies had formed in the central and northern Salish Sea, including the San Juan Islands (n = 3), Gulf Islands (n = 3) and northern Strait of Georgia (n = 2). Brandt's Cormorants only bred sporadically in the San Juan Islands at Flattop Island (1928), Matia Island (1940) and Lopez Island (<1953). Evidence of breeding in the central Salish Sea by all 3 cormorant species suggested resettlement of individuals from colonies on the outer west coast of Washington through the Strait of Juan de Fuca. Subsequent expansion by Pelagic and Double-crested cormorants in the central and northern Salish Sea suggested local growth after colonization, although impacts from human disturbance and predators affected certain colonies. Reduced harvesting by the shrinking population of indigenous peoples at cormorant colonies on the outer coast of Washington likely prompted colonization of the Salish Sea.
Central questions of ecology concern how and why organisms distribute themselves in time and space. Answers to these questions contribute to our understanding of the fitness of organisms and provide baseline information against which to compare future distributions in the face of environmental change. Here we characterize daily and yearly fluctuations in counts of Glaucous-winged Gulls (Larus glaucescens) in 5 connected habitats associated with a large seabird colony in the Salish Sea, Washington State. Daily fluctuations in the 5 habitats differed markedly and were driven by day of year, time of day, solar elevation, tide height, barometric pressure, and ambient temperature. Seasonal peak numbers in all habitats occurred between mid-March and mid-September. No gulls remained on their breeding territories past late September, and few gulls remained on the island between late September and mid-January. Numbers rose steadily from early February to March.
The freshwater sculpin species Cottus gulosus and Cottus perplexus present a challenge to biologists because of their overlapping sympatric distributions, morphological similarity, and historical inconsistency regarding species limits and ranges. We applied linear morphometric analyses in conjunction with meristic and discrete character counts to 1) assess the validity of previously cited diagnostic characters, 2) test multivariate combinations of characters to elucidate novel diagnostic characters useful in distinguishing the 2 species, and 3) apply these diagnostic characters to identify previously unidentified specimens obtained from Washington streams, where the 2 species occur in sympatry. Our analysis of 270 Cottus specimens encompassing the range of both species uncovered little support for the diagnostic utility of previously cited characters, although significant differences between mean measurements for each group were detected in the proportion of individuals with palatine teeth and a median chin pore, as well as in mean mouth-width to body-width ratio. Additionally, we were unable to detect linear transformations of continuous measurements that could be used to reliably identify individuals of these 2 species. These results prevented us from confidently identifying the unknown Washington specimens and illustrate that multi-locus phylogenetic studies are needed to assess species boundaries for these morphologically similar fishes.
The Sand Roller (Percopsis transmontana), has not been abundant in the Snake River since it was first found in the system in the 1950s, but its population has apparently increased in recent years. As a result, we initiated a study to better understand its ecology in habitats of Lower Granite Reservoir. From November 2014 to October 2015, Sand Rollers were present along shorelines, with peak abundance being observed during spring months. Logistic regression analyses showed that Sand Rollers were more likely to be present in shoreline habitats at temperatures ≤18.4°C. Fish were found over a range of substrates, with the lowest odds of fish presence being associated with riprap, which is common in hydropower reservoirs. From length-frequency analysis, we suggest that Sand Roller spawning occurs primarily in May and early June. Assessment of Sand Roller diets found dipteran (chironomid) larvae and pupae were the most important prey consumed by all sizes of Sand Rollers, but Opossum Shrimp (Neomysis mercedis) were also prominent in diets of larger fish in shoreline and offshore habitats. At a time when the populations of so many native species are in decline, the increase of the Sand Roller population in the lower Snake River represents a positive, yet curious occurrence.
Monitoring avian populations over both the reproductive and non-reproductive seasons is required to better understand population changes. Obtaining baseline data in remote sites, however, is often difficult during the non-breeding season, especially in ice-driven ecosystems. We determined annual changes in numbers of over-wintering sea duck and large-bodied gull species and identified their main areas of concentration at one of the Pribilof Islands (St. Paul) in the Bering Sea. Formally trained local citizens undertook weekly counts using standardized methods over 3 non-breeding seasons (2008–2009; 2009–2010; 2010–2011) from late autumn to early spring. Sea ducks and large-bodied gulls were present nearshore in considerable numbers from November to January, and maximum counts usually occurred between February and March when sea-ice cover is at its maximum near the Pribilof Islands. We found that one-time counts would underestimate some species (Bufflehead, King Eider, Harlequin Duck), their numbers having peaked earlier in the non-breeding season. Across years, Harlequin Duck (47% occurrence; maximum of 476 total individuals at all sites), Long-tailed Duck (23%; maximum of 627) and King Eider (18%; maximum of 136) were the most common and abundant species. Buffleheads (maximum of 24 individuals) and White-winged Scoters (maximum of 500 individuals) were less common (<5% occurrence), and had distinctive localized distributions in intertidal and lagoon habitats. Only Harlequin Ducks and large-bodied gulls varied annually, with nearly twice as many birds in 2011 as in 2008. Large-bodied gull concentrations (maximum of 1230 individuals; primarily Glaucous-winged Gulls) were mostly associated with dockside and outfall fish offal rather than landfill. Given that large-bodied gulls foraged in the same sites and monthly peaks mirrored those of sea ducks, kleptoparasitism is a potential problem, especially in absence of fishery discards. Our study fills a gap in the current understanding of regional waterfowl and large-bodied gull status during the non-breeding season in the Pribilof Islands, an important over-wintering location.
During the period 1996–2003, a population of introduced Salvelinus fontinalis was eradicated from a montane lake in Mount Rainier National Park, Washington State, USA. Using mostly gill-nets, 2185 fish were removed. Snorkel and visual encounter surveys (n = 10 and 6, respectively) were completed 1996–2001, to document the apparent abundances of amphibian species present in the lake and an adjacent shallow pond during fish presence and removal. During this period only 7 Ambystoma gracile larvae and 6 Rana cascadae adults were observed in the lake; no amphibians were observed in the pond. After fish removal, lake snorkel and visual encounter surveys (n = 9 and 10, respectively) conducted between 2004 and 2015 collectively documented the apparent increase in abundances of A. gracilie (n = 398), A. macrodactylum (n = 68), Ambystoma spp. (n = 184), Rana cascadae (n = 357), and Ascaphus truei (n = 12). Pond visual encounter surveys conducted between 2005 and 2012 documented the increased presence of Ambystoma spp. (n = 110) and Rana cascadae (n = approximately 5600 ) larvae. Although the number of amphibian species detected and their apparent abundances varied among surveys and years, the abundances of the amphibian species in Hidden Lake increased markedly after removal of the introduced fish population.
We report details of 3 food caches created or retrieved by a pair of Common Ravens (Corvus corax) near their active tree nest in the Pattee Canyon Recreation Area, Missoula County, Montana, during spring of 2016. Caches were located in 3 different 30–35 m tall Ponderosa Pines (Pinus ponderosa). Caches were pieces of meat placed 1.0–1.5 m from the trunk on large lateral limbs at least 20 m above ground, and were 70–100 m from the nest tree. One cache was created by the non-incubating adult early in the incubation phase of nesting, and probably was fed to the incubating adult by its mate. The other 2 caches were retrieved early in the nestling phase, at least 1 of which was delivered directly to the brood at the nest. At least 2 of the caches were hidden under pieces of bark and lichen placed on the cached meat, probably to reduce likelihood of their detection and theft by other forest birds and mammals. The tree caches shared some characteristics of ground caches created elsewhere by nesting Ravens: (1) caches were within 100 m of nests; and (2) caches were often hidden or covered with vegetation. These appear to be the 1st published observations of tree caches created and retrieved by Common Ravens near their active nest. Our observations also suggest that caches may be used by the adults to feed themselves as well as their young.
Surf Scoter (Melanitta perspicillata), a sea duck that winters commonly along the coast of the Pacific Northwest states, was observed exhibiting unusual foraging behavior in the swash zone of a beach on the Point Reyes Peninsula, California, in mid-January of 2015. This note reviews the literature involving scoter foraging behavior, discusses the likely prey items targeted, and the potential risks posed by such behavior.
Quantifying prey taken by Pacific Marten (Martes americana caurina) helps to understand local habitat requirements of the species. We collected 250 scat samples associated with at least 53 marten in a salvage-logged Lodgepole Pine (Pinus contorta)-Bitterbrush shrub (Purshia tridentata) forest in south-central Oregon. The frequency of occurrence of food items included 98.0% mammals, 36.0% arthropods, 23.2% birds, 9.2% plants, 2.0% hares and rabbits, and 0.8% reptiles. Among mammals, 72.4% were vole-sized and 47.2% squirrel-sized. Chipmunks (Neotamias spp., 27.6%) and ground squirrels (Spermophilus spp., 28.0%) had the highest occurrence by size group, respectively. Frequency varied little between summer and winter. Male marten preyed on a greater proportion of mice (Peromyscus spp.) than females, especially in summer, and in winter females preyed on a greater proportion of voles (Microtus spp.) than did males. Female marten also preyed on a greater proportion of birds in winter than did males, whereas males had a greater proportion in summer. We compare our findings with a concurrent study in northeastern Oregon and discuss the importance of slash piles from the indirect evidence in the frequently logged forest type to help inform habitat management of the species and prey.
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