The endangered Southern Resident Killer Whale (Orcinus orca, SRKW) is an iconic species in the Pacific Northwest. Although many ecological aspects of this population have been studied, why SRKW perform above-surface “percussive” behavior such as breaching, cartwheeling, pectoral-fin slapping, tail lobbing, and dorsal-fin slapping remains unclear. In the present study, we observed SRKW in Haro Strait, Washington, to evaluate trends in percussive behavior by age and sex class during the summer of 2016, and used long-term data (1996–2016) to compare the relationship between the seasonal frequency of percussive behaviors and the abundance of Chinook Salmon (Oncorhynchus tshawytscha) the primary food source of SRKW. Over the summer season in 2016, we documented 24 encounters involving percussive behavior. We found a significant difference between ages and sexes in the rate of percussive behaviors performed, with adult females performing the most behaviors among these groups, and tail slaps comprising the most frequent behavior performed. We also found a significant positive relationship between the rate of percussive behaviors and Chinook Salmon abundance in the Salish Sea over the past 2 decades. These findings present a preliminary investigation into the potential for behavioral observations to serve as indicators of population-level health or behavioral trends, which could be important for this population's conservation.

We present results from the first 5 y of a long-term monitoring study of recovering populations of the North American River Otter, Lontra canadensis, in Marin County, California. Historically present, but extirpated due to trapping and habitat loss, this apex aquatic predator is recolonizing coastal, lentic, and riverine habitat areas around San Francisco Bay. Using camera traps and a community science effort, we estimated an annual minimum population size at each of 14 focal study sites (FSS). Based on those estimates over 5 y, we developed a new Bayesian-statistics model to estimate population parameters for each FSS, including initial population abundance, annual rate of change in abundance, and probability that abundance is in decline. Our results show significantly different changes in abundance among the various FSS, with annual rates ranging from a high of 0.86 to a low of –0.44. Using a Random Forest framework, we then investigated the relative value of select spatial, environmental, and anthropogenic variables as predictors for each FSS population parameter. In our analysis spatial factors, and specifically latitude, were the best predictor of differences in FSS population parameters. Higher latitudes correlated with higher initial population abundance, greater annual increase in abundance, and lower probability that abundance is in decline. Our results provide new information about the rate and pattern of natural River Otter recolonization of areas from which they have been absent for decades. The results also serve as a demonstration of an approach to long-term monitoring, with the goal of increased understanding of the ecological function of River Otters in the San Francisco Bay Area.

We monitored California Sea Lions (Zalophus californianus) in the lower Columbia River Basin from 1997 to 2018 to document their seasonal and annual occurrence in the estuary and to determine what fraction of that population was preying on salmonids (Oncorhynchus spp.) at Bonneville Dam on the Columbia River or Willamette Falls on the Willamette River. Based on periodic haul-out counts at the South Jetty (river km 0) and the East Mooring Basin (river km 25), we found that since 1999, several thousand California Sea Lions regularly hauled out at the mouth of the river, particularly during autumn months, but similar numbers did not occur inside the estuary until 2013, and then primarily during spring months. Haul-out use of the East Mooring Basin followed a bimodal pattern, with peaks during autumn (northward migration) and spring (southward migration), and troughs during summer (breeding season) and winter. Based on trapping and branding 2651 California Sea Lions at the East Mooring Basin through 2016, and brand resights at Bonneville Dam (river km 235) and Willamette Falls (river km 206) through 2017, we found that only 6.5% of the sea lions in the estuary recruited into the population of upriver “problem” animals that preyed on threatened and endangered salmonids. Besides documenting long-term abundance and movement patterns of sea lions, our monitoring program served as a research platform for other scientists and provided the foundation for California Sea Lion management policy in the Columbia River Basin.

Size dimorphic ungulates often display ecological differences attributed to body size. We predicted that male elk should select foraging sites containing more abundant forage than sites selected by smaller-bodied female and juvenile elk. To test this prediction, we estimated forage biomass at bite stations grazed by juvenile, adult female, and adult male Roosevelt Elk (Cervus elaphus roosevelti). Moreover, we examined the potential confounding influences of number of bites taken and group size on forage biomass at bite stations. We measured forage biomass associated with focal observations of 310 grazing elk (55 juveniles, 145 females, 110 males) in 2 meadow complexes in Redwood National and State Parks, California, 2008–2011. Analyzing a linear mixed effects model, our fixed effects showed that forage biomass at bite stations grazed by males tended to be greater than that of bite stations grazed by juveniles and females. When we considered the additional uncertainty from random effects, there was considerable overlap in 95% confidence intervals of estimated forage biomass at bite stations grazed by juvenile, female, and male elk. Therefore, the positive correlation between age-sex classes and forage biomass was weak. There also was no influence from number of bites taken at bite stations or group size on forage biomass at bite stations. When forage was limited, body size had a weak influence at bite stations grazed by juvenile, adult female, and adult male Roosevelt Elk.

We examined changes in density, distribution, and size of migratory sculpins (Coastrange Sculpin [Cottus aleuticus] and Prickly Sculpin [C. asper]) in 4 small lowland urban tributaries following the removal of instream barriers. In 3 of the streams, a complete or partial barrier to upstream movements of migratory sculpins was removed. In the 4th stream where sculpin were not known to be present, the lower reach was daylighted (stream channel was reconfigured from an underground culvert to a more natural stream channel at the surface). In Lyon Creek, where a partial barrier was removed, sculpin densities upstream of the barrier site increased only slightly. Poor habitat conditions in this stream section may have limited recovery. In Taylor and Zackuse Creeks, where barriers were also removed, Coastrange Sculpin quickly colonized the stream section upstream of the barrier site and densities became similar to or higher than downstream study sections. In the daylighted Mapes Creek, both sculpin species were common throughout the new channel shortly after the project was completed. In both Lyon and Taylor creeks, body size of migratory sculpin in the upstream section decreased dramatically following barrier improvement. Prior to barrier removal, only a few large sculpin migrated upstream; whereas, after barrier removal sculpin of all sizes were able to move upstream except young-of-the-year. Our results indicate that migratory sculpin have the ability to recolonize new habitats shortly after connectivity is restored, but habitat quality may limit sculpin use of newly accessible areas.

I observed Black-billed Magpies (Pica hudsonia) in a residential backyard in Montana during November-December 2019 and February 2020, as they cached food 10 times in a snow cover 10- to 12-cm deep and recovered 3 caches from the snow. The magpies carried food items up to 7 m from a food source before caching them, and tended to cache more closely to the food source when alone rather than in the presence of other magpies. Most of the snow caches were on the ground, but 1 cache was made 1.5 m above ground in a snow-covered vine thicket, and a 2nd cache at the same height in snow accumulated on the roof of a parked trailer. Cached foods included chicken scratch (grains and cracked corn), sunflower seeds, crab apples, dried mealworms, and commercial suet. These observations appear to constitute the 1st report of Black-billed Magpies caching food in snow.

Social rank and personality (consistent behavioural traits) can influence access to resources that could be critical for fat accumulation and survival from disease. For Little Brown Bats (Myotis lucifugus) recovering from the fungal disease white-nose syndrome, understanding behavioural dynamics may also be important for maintaining animals in captivity for conservation research. We hypothesized that Little Brown Bats will exhibit social structure in captivity, and that social rank and personality affect feeding behaviour. We predicted that bats would arrive at the feeding dish in a similar order each night and that higher ranked and more active individuals would spend more time and feed more frequently at the food dish. Bats arrived at the feeding dish in a similar order each night, suggesting that social rank may affect feeding in captive bat colonies. However, neither the order of arrival or personality correlated with feeding behaviour. We recommend that future studies test for the influence of dominant-subordinate relationships on social structure in captive and free-ranging insectivorous bats.

On 3 August 2018, a single specimen of the Dusky-footed Woodrat, Neotoma fuscipes, was collected as the 1st occurrence of the species in Nevada.