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Information on marine mammals and marine birds in US Pacific Northwest waters is limited but necessary to assess potential impacts from proposed and planned human activity (for example, cable installation, energy and port development) as required by regulatory permitting processes, particularly relative to recent plans for offshore wind development. We conducted daily opportunistic, non-systematic observations of marine mammals and marine birds in autumn 2014 and of marine mammals in summer 2015 to meet mitigation and monitoring requirements associated with a geophysical site characterization survey for a proposed offshore wind floating platform demonstration project off Coos Bay, Oregon. Two biologists completed observations during daylight with the naked eye and reticle binoculars from a 17-m vessel between Coos Bay and the proposed platform site 30 km offshore. In 2014, 1058 h (3244 km) of observation occurred during 3 October through 4 November, with 1182 h (4367 km) observations conducted from 10 July through 28 August 2015. In total, 543 groups (approximately 1389 individuals) representing at least 14 marine mammal species and 7444 groups (approximately 18322 individuals) representing at least 22 marine bird species were observed. Sighting rates (number of individuals observed per 100 km of observation) were higher for nearly every species of marine mammal in summer 2015 than autumn 2014. An extralimital sighting of 25 Bottlenose Dolphins (Tursiops truncatus) and 5 sightings of rare transient Killer Whales (Orcinus orca) were documented. Results address a gap in site-specific marine mammal and marine bird baseline occurrence data and information required to assess effects of proposed offshore wind development and other human-related activities near Coos Bay, Oregon, as well as climate and oceanographic changes.
KEYWORDS: diet, Eel River, group foraging, herpetofauna, invasive species, North American River Otter, Northern California, Rough-skinned Newt, Sacramento pikeminnow, Northwestern pond turtle
We identified species and approximate size of prey items in 109 digital photographs of North American River Otters (Lontra canadensis) hunting in a 2-km stretch of South Fork Eel River, California, from January 2017 through December 2021. Over the 5-y study, 403 observations of River Otter social-group types and sizes were recorded, including singles, family groups with pups, and groups of up to 8 adults. An average of 3.0 River Otters per week (sx = 0.2, range 1 to 13 individuals) were observed in the study area. Eleven species of prey were taken by River Otters, including primarily, Sacramento Pikeminnow (Ptychocheilus grandis; 54.1% of 109), followed by crayfish spp. (24.8%), Pacific Lamprey (Entosphenus tridentatus; 10.1%), herpetofauna (6.4%), and less-frequently taken fish species (4.6%). Contingency table frequencies indicated Sacramento Pikeminnow and crayfish were taken more in months of low water flows in the river. Herpetofauna prey included 1 American Bullfrog (Lithobates catesbeinus), 2 Foothill Yellow-legged Frogs (Rana boylii), 1 Northwestern Pond Turtle (Actinemys marmorata), and 3 Rough-skinned Newts (Taricha granulosa), apparently with no ill effects to the otters. Sacramento Pikeminnows were captured by social groups of 2 and 3 or more River Otters more often than expected, and by single otters and family groups less often than expected; whereas crayfish were captured by single otters and family groups more often than expected, and by social groups of 2 and 3 or more, less often than expected. Different River Otter social-group types and sizes captured smaller (<30 cm) and larger fish (≥30 cm) at similar frequencies.
KEYWORDS: Ambystoma californiense, California tiger salamander, dispersal, fluorescent powder, Metamorph, migration, orientation, Santa Rosa Plain, Sonoma County, vernal pool
The endangered Sonoma County population of the California Tiger Salamander, Ambystoma californiense, undergoes migrations between breeding pools and upland dry-season refugia. Orientation in this species during breeding migrations has been addressed minimally in previous studies, and literature is particularly sparse concerning newly metamorphosed juveniles. Previous works have not addressed the ability of metamorphs to orient or the way in which they search for upland refugia. The initial migration from natal pools to uplands following metamorphosis has been identified as a crucial life-history juncture for the persistence of this species. We evaluated fine-scale movements of newly metamorphosed California Tiger Salamanders as they moved away from breeding pools by capturing salamanders with a drift fence and then tracking individuals with fluorescent powder. Here we show that newly metamorphosed juveniles do not move randomly, and that they can re-orient to their upland migration after being interrupted and disoriented. Further, we demonstrate that while searching for burrow refugia, metamorph movement can be characterized as a correlated random walk.
Harbor Seals (Phoca vitulina) are widespread and abundant predators in Washington State and their diet is of interest given their potential impact on fish species of concern. Although the diet of this species has been well described, no data exist for most of the Pacific coast along the Olympic Peninsula and the Strait of Juan de Fuca. Here, we provide diet data (via DNA metabarcoding and hard parts) of male and female Harbor Seals from the northwestern coast of the Olympic Peninsula and the western Strait of Juan de Fuca, based on 59 scats collected during December 2020–March 2021. Despite the difficulty in collecting usable scat for hard-parts analysis during the winter months, we were able to determine diet in all collected scats via DNA metabarcoding, highlighting the value of this technique. Based on DNA metabarcoding, the species most frequently consumed by Harbor Seals were Lingcod (Ophiodon elongatus), Pacific Herring (Clupea pallasii), Kelp Greenling (Hexagrammos decagrammus), and Giant Pacific Octopus (Enteroctopus dofleini). Although based on a small sample size, this prey composition differs from that of other sites in the state, supporting the view of Harbor Seals as opportunistic central-place foragers that consume locally and seasonally available prey. Male and female Harbor Seals also appeared to differ in their diet, although the small sample size of this study limits our ability to make a direct comparison. Our results highlight the need for additional studies in the Olympic Peninsula to fully describe the diet of these predators as well as variations among seasons and between sexes.
I provide the 1st account of flights by Little Brown Myotis (Myotis lucifugus) transitioning from autumn roosts to noncavernous hibernacula. I tracked all or part of the flights of 5 bats, 3 males and 2 females. Two bats hibernated at their last location, 2 additional bats presumably hibernated at their last locations, which were near known hibernacula, and 1 bat was traveling toward that same hibernation area when fog prevented us from following her inland. Bats traveled an average of 26.9 km between day roosts and their hibernaculum or presumed hibernaculum (range = 21.2 to 36.3 km); corresponding straight-line distances averaged 16.2 km (range = 9.4 to 24.2 km). Travel speeds for 4 bats while they were actively tracked averaged 17.3 km h–1 (range = 10.2 to 25.9 km h–1). Two bats took detours along the way, spending at least 35 min at those locations before resuming their journeys. Average time from when bats left their day roost until they hibernated or I lost the signal was 2.2 h (SD = 1.6, range = 0.8 to 4.3 h). Bats followed coastlines, creek drainages, and ridgelines while traveling over land and used peninsulas and islands when traveling over the ocean, possibly to minimize the distance they traveled over open water.
In this note, I report on my observations of a pair of Canada Jays (Perisoreus canadensis) gathering live engorged female Winter Ticks (Dermacentor albipictus) from the recent bed of a yearling Moose (Alces alces) and flying into the adjacent woods to cache the ticks before returning for more. The Moose bed was on snow and contained loose hair and blood-stained snow as well as the engorged ticks. I found 12 additional beds on snow during the next 48 h within 250 m of the original bed, and all contained loose hair and blood-stained snow, but no ticks. Jays may routinely visit Moose beds on snow in spring because they recognize them as a potential source of food. Moose, however, may not be present during spring in many jay territories, so access to engorged ticks at beds is probably opportunistic and unreliable.
The American Avocet (Recurvirostra americana) is a striking black-and-white shorebird that occurs seasonally in southern Canada from British Columbia to western Ontario. Its northern limit in Alberta is near the latitude of Edmonton, and its typical preferred habitat is lakes similar to Beaverhills Lake, a Ramsar wetland 60 km east of Edmonton. In 2009, after 45 y of field studies of shorebirds and their avian predators at Beaverhills Lake, I switched study locations to Cooking Lake. From 2009 to 2023, I walked a seasonal bird survey along a 3–5-km section of Cooking Lake shores. The spring arrival of Avocets coincided with the first open water, and they stayed at the lake until late October, 3–4 wk after the latest date recorded in provincial handbooks. Avocet reproduction at Cooking Lake was presumed to be limited by the scarcity of island nesting habitat. Non-nesting aggregations were estimated at a maximum of 6000 birds. Foraging and roosting flocks were monitored for interactions with raptors, but in 60 y of walking the shores of both Alberta lakes, I have never seen an avian raptor seize an Avocet, nor did I find any plucked remains of Avocets.
Species-specific knowledge of climate needs and associations is crucial to inform amphibian conservation efforts. A recent study conducted 2 survey sessions at 5-y intervals (2013 and 2018) for Western Toad (Anaxyrus boreas) breeding activity at 124 ponds in northern Idaho and northeastern Washington. The 2nd sampling session detected Western Toad breeding activity at 41% (n = 7) of sites where breeding activity was detected during the 1st sampling session (n = 17). During the 2nd survey, breeding activity was detected at just 1 of 107 sites where it had not been detected during the 1st sampling session. Second sampling session detections were disproportionally skewed north in latitude to a portion of the study area that is documented to have a relatively high proportion of cool-air microclimates. We hypothesized that Western Toad breeding activity would be more likely to persist at locations which are relatively cooler than mean climate variables of other study sites and tested this hypothesis by running a logistic regression of climatic variables in the program R. Mean annual minimum temperature at the 4-km scale was the single predictor variable for detection of Western Toad breeding persistence between 2013 and 2018. We recommend future work continue to document demographic trends for Western Toads and managers incorporate Western Toads into climate microrefugia management plans.
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