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Riparian systems support disproportionately high biodiversity and are critical for avian conservation in the western United States, yet much historic riparian habitat has been lost or degraded. Restoration of riparian vegetation and associated ecological processes is a high priority, and birds can serve as indicators of restoration success. Here, we analyze data from 17 y of constant-effort mist netting at an urban riparian restoration site to examine changes in capture rates from 2001 to 2017. Capture rates of 4 of 17 species commonly using the site during autumn, and 6 of 14 species using the site during winter, increased over time, and more so in the restored area compared to the mature riparian reference area. This suggests that these birds increased use of the restored habitat area as riparian tree and shrub plantings matured. Birds that responded positively to restoration included several species that breed in and are considered indicators of coniferous forest habitats (Purple Finch, Oregon Junco, Hermit Thrush, and Fox Sparrow) that often inhabit riparian areas during the non-breeding season. Species that breed in riparian habitat did not show as consistent or as strong of a non-breeding season response to restoration. Riparian birds associated with open, wet herbaceous vegetation (Common Yellowthroat and Lincoln's Sparrow) declined in the restored area in autumn while maintaining stable capture rates in the reference area. Three species of finch (Spinus spp.) used the restored habitat, and the site as a whole, in far fewer numbers during the autumn dispersal and migration period in the years following restoration, likely owing to invasive teasel removal efforts. Taken together, these results suggest that restoration actions can result in trade-offs that benefit some birds while reducing suitable habitat for others. Birds complete important activities in the autumn and winter, including dispersal, migration stopover, and molt, so restoration work that supports bird populations during the non-breeding season, even at relatively small urban sites, can make important contributions to their conservation. However, managers should consider the goals of restoration actions in the context of species- or guild-specific responses to restoration-associated changes in vegetation structure.
The Black Oystercatcher is a large shorebird found along the west coast of North America. Because of its small global population size, low reproductive rate, and dependence on rocky intertidal habitats, it is considered a “species of high conservation concern” and may act as an indicator of intertidal ecosystem health. In 2015, Portland Audubon initiated a 3-y shore-based population survey in Oregon building upon long-term monitoring previously conducted by the US Geological Survey (USGS) and others. The objectives were to: (1) estimate the current minimum population of breeding Black Oystercatchers in Oregon and compare to previous estimates; (2) document oystercatcher abundance on shoreline adjacent to the Oregon's system of Marine Reserves (MRs) and Marine Protected Areas (MPAs); and (3) describe the spatial distribution of breeding oystercatchers along the coast. We targeted all rocky shoreline along Oregon's coastline to conduct abundance surveys each spring from 2015–2017. A total of 75 survey routes were sampled using a standardized land-based survey protocol. Trained volunteer community scientists conducted the majority of the surveys. We used N-mixture statistical models to estimate oystercatcher population size and probability of detection. Population estimates from the best-fitting models were consistent, with estimates ranging from 506 oystercatchers in 2016 (95% credible interval, 463–560) to 629 (548–743) in 2015. These estimates described a small but stable population. Probability of detection remained consistent across years (ranging from 0.51 to 0.53). Breeding density of oystercatchers was higher in southern Oregon. Oystercatcher abundance adjacent to MRs-MPAs accounted for between 12.4–18.3% of the total population estimate, which was lower than expected (approximately 25%). Subsequent conservation efforts for Black Oystercatchers in Oregon could be successful by focusing on limiting human disturbance, particularly on the north and central coasts, and protecting core habitats on the south coast where much of the population resides.
Bird-window collisions occur across North America and are estimated to kill hundreds of millions of birds annually. Previous studies show that collisions occur non-randomly and can be influenced by building characteristics, time-of-year, and species-specific physiology and behaviour. Much of the available research is based in northeastern North America, though different species and habitats in the West may be affected differently. We collected strike data from 2 buildings in Victoria, British Columbia, from June to October 2018. We found that window width was positively related to the probability of a strike occurring, whereas vegetation distance to window, window aspect, and the building at which it occurred did not predict strike probability. A substantial increase in strikes occurred in September and October, which coincides with peak migration on Vancouver Island, and suggests that migration influences collision risk to bird species.
The Pacific Sand Lance (Ammodytes personatus) is a major component of the forage base for many species of marine birds, mammals, and fishes. Despite its ecological importance, relatively little is known regarding basic biology or life-history parameters for this species. Information on age and growth is particularly lacking for Pacific Sand Lance in the Salish Sea, an inland sea that encompasses the San Juan Archipelago in Washington State. Here, we present information on age and growth of Pacific Sand Lance from this region and then contrast it with a previous study based in Cook Inlet, Alaska. These 2 regions comprise the latitudinal extremes of the Gulf of Alaska large marine ecosystem. We found evidence for possible differences in growth of Pacific Sand Lance between the 2 regions, with San Juan Island fish generally being smaller at age than fish in Cook Inlet. We interpret these results with respect to regional and temporal differences in environmental conditions and resource availability linked to duration and magnitude of seasonal production, which we hypothesize affects the period of winter dormancy employed by this species as a strategy to cope with resource limitation.
The Common Wall Lizard (Podarcis muralis) has existed in southwestern British Columbia since 1967, but expanded its range rapidly in the last decade. In 2006, P. muralis was thought restricted to 4 populations on southeastern Vancouver Island: 3 on the Saanich Peninsula and 1 in the Triangle Mountain area. However, increased reporting and exploration led to the recognition that these populations have merged. Further, P. muralis have also appeared along the eastern side of Vancouver Island north to Campbell River; and on Denman Island. In 2015, P. muralis was also reported from two BC mainland locations: Osoyoos in the southern Okanagan, and the city of Vancouver. Introduced lacertid populations are reported to spread from their points of origin at a relatively slow rate (∼1 km every 10 y), so given that P. muralis has been found at least 200 km north, 300 km west, and from Vancouver Island to Denman Island and the British Columbia mainland over the last 52 y, human-assisted dispersal likely contributed to its apparently rapid radial expansion in southwestern BC. As they expand into rural and protected areas on Vancouver Island, P. muralis may have increasing opportunities to interact with the native Northern Alligator Lizard (Elgaria coerulea). Where E. coerulea and P. muralis coexist on southern Vancouver Island, the latter seems more abundant, which raises concern and warrants study.
Southern Torrent Salamanders (Rhyacotriton variegatus) are a cold, headwater-inhabiting amphibian native to the Pacific Northwest. This genus of salamanders is considered highly aquatic, even in postmetamorphic stages, although instances of terrestrial movement have been observed. This note reports our opportunistic field observations for terrestrial movement in R. variegatus, which primarily occurred in the vicinity of Marys Peak, Benton County, Oregon.
We report the 1st documented occurrence of California Kangaroo Rats, Dipodomys californicus, in the state of Nevada. These captures, located in juniper woodland habitat between 1627 and 1900 m in elevation, represent both the easternmost-known occurrence and the highest reported elevation for this species.
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