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National parks play a key role in conserving species by providing landscapes where threats from anthropogenic disturbance are reduced. In a recent study of 3 large wilderness parks in the Pacific Northwest, nearly all landbird species were found to be stable or increasing. Nonetheless, contemporary results from the Breeding Bird Survey and mark-recapture studies fuel concerns that some landbirds in the Pacific Northwest are trending in sync with many North America species in widespread decline. Although landbird populations might be thriving in large parks with extensive old-growth forest, those in smaller parks with less intact wilderness and higher ratios of edge-to-interior habitat might reflect the stressors inherent in more human-dominated landscapes. We conducted landbird point-count surveys from 2005 to 2016 in 2 national historical parks situated in the more human-dominated landscapes of this region, San Juan Island National Historical Park and Lewis and Clark National Historical Park. Established primarily to protect cultural resources, these parks lack old-growth forest and consist of relatively small parcels embedded in fragmented, multi-use landscapes. Here, we apply recent developments in point-count analysis to estimate trends in population density for 50 landbird species commonly detected in these small parks, including lagged effects of precipitation and temperature on the annual density of each species, and effects of survey conditions on species detection. All but 3 species exhibited stable densities in both parks, and more than half of the populations analyzed clearly increased in density over the study period. Notable exceptions were single-park declines in Olive-sided Flycatcher (Contopus cooperi), Northern Flicker (Colaptes anratus), and Hutton's Vireo (Vireo huttoni). Annual variation in population density was often related to climate, with generally positive responses to a recent deficit in annual precipitation-as-snow, and more variable responses to higher mean spring temperature. These results reinforce trends estimated for 3 large national parks in the Pacific Northwest, suggesting recent stability of landbird populations in parks of this region, independent of park size or setting.
We studied some of the relationships between federally listed fall Chinook Salmon, Oncorhynchus tshawytscha, endemic Sand Roller, Percopsis transmontana, and non-native Smallmouth Bass, Micropterus dolomieu, in Lower Granite Reservoir on the Snake River. Because of its recent reappearance and population increase, the Sand Rollers could be filling the role of a “native invader” in the reservoir food web. We speculated that Sand Rollers could either negatively affect fall Chinook Salmon by potentially competing with them for resources in shoreline habitats or, alternatively, benefit the salmon by providing a buffer against Smallmouth Bass predation. Nighttime beach seining showed that habitat use by fall Chinook Salmon and Sand Rollers overlapped completely in spring when both species were present along shorelines. Diet data from stomach samples also showed high overlap, but data on stable isotopes of 13C and 15N suggested that each species could be obtaining much of their dietary energy from different reservoir locations. Although habitat and diet overlap are evidence of competition, diel and spatial partitioning of resource use between fall Chinook Salmon and Sand Rollers may act to reduce potential competition. Analyses of Smallmouth Bass diets showed that fall Chinook Salmon and Sand Rollers comprised the majority of prey fish consumed by bass. Across years, as Smallmouth Bass increased their consumption of Sand Rollers (range 0.219 to 0.392 fish smallmouth-1 day-1), they decreased their consumption of fall Chinook Salmon (range 0.114 to 0.050 fish smallmouth-1 day-1). The greatest effect Sand Rollers may have on fall Chinook Salmon in Lower Granite Reservoir is to serve as a buffer against Smallmouth Bass predation.
Recent deep-water surveys of the continental slope in the Bering Sea and the eastern North Pacific, conducted by the US National Marine Fisheries Service, Alaska Fisheries Science Center, and Fisheries and Oceans Canada, have broadened our understanding of the ichthyofauna in the region. Herein, we report significant new records of 2 species of skates based on morphological and molecular data. For Bathyraja spinosissima, the White Skate, we describe 2 specimens: a neonate male that constitutes a northern range extension for the species to Alaska in the Bering Sea; and an adult male representing a new record for the species in British Columbia. For B. microtrachys, the Fine-spined Skate, we describe 5 males taken in a single haul that represent the 1st record of the species in British Columbia. These specimens had been previously misidentified as B. violacea, the Okhotsk Skate, a species known only from the western Aleutian Islands and the western North Pacific.
Prior to 2013, only 5 verified records of the Common Sharp-tailed Snake (Contia tenuis) existed in western Washington State, with only 1 observation from the San Juan Islands. Our objective was to broaden our knowledge of the Common Sharp-tailed Snake in the San Juan Islands. We installed cover boards in suitable habitats and checked them as circumstances permitted. We engaged local landowners by providing them with cover boards and asking them to check the cover boards to increase the likelihood of detection. We recorded 9 Common Sharp-tailed Snake observations between 2013 and 2017, including the 1st record for San Juan Island on Cady Mountain. We also observed the species on Mount Dallas and Young Hill on San Juan Island, and we increased the area of occupancy on Turtleback Mountain on Orcas Island by discovering 2 new sites. Conifer-encroachment resulting in habitat loss, along with house cats may threaten Common Sharp-tailed Snake populations at these sites. More study of these threats is needed to inform Common Sharp-tailed Snake management. Our findings imply a broader occurrence of this species in the San Juan Islands. We recommend broader surveys of occupied and other islands in the group to refine our knowledge of the distribution and habitat use of this species.
I observed a Western Terrestrial Garter Snake (Thamnophis elegans) attacking a large (approximately 9-d-old) nestling Dark-eyed Junco (Junco hyemalis) on 7 July 2018 near Rattlesnake Creek, Missoula County, Montana. The snake held the stillliving nestling by its head (the head was mostly enveloped by the snake's jaws) and continued to do so for 3 min before it released the now-dead nestling when disturbed by my presence. The dead nestling exhibited skin wounds on the neck but no other superficial injury. Predation on birds by Western Terrestrial Garter Snakes is infrequently reported, and I found only 2 other reports of predation on juncos by this snake species.
Forest birds are sensitive to habitat change and may be suitable for measuring responses to retention forestry. I present the short-term effects of 6 treatments in a 6 block randomized design experiment on 15 breeding small bird species in mature Douglas-fir (Pseudotsuga menziesii) forests in western Washington and Oregon, 1994–2001. The 13-ha treatment stands contained aggregated (A) green-tree retentions of 100, 75, 40 and 15%, and a dispersed tree distribution pattern (D) of 40 and 15% retention. I compared numbers of entire singing bird territories (abundances) mapped inside sampling plots in post-(2-y x̄) and pre-treatments (1 y). Species richness significantly declined in both 15% treatments. In the 15%D treatment, significantly lower richness and lower species similarity were less than A treatments with ≥40% retention, and significantly lower species diversity was less than the other treatments. The size of decline of abundances of canopy-associated species (summed members) increased with successively lower tree retention; the cavity-nesting species declined with lower snag retention in treatments ≤40% retention; and there was no response for species associated with understory vegetation, but medians of the percentage change in abundance of understory species were negative in cut treatments. There was no detectable difference in treatment effects between tree distribution cut patterns. Greater amounts of tree retention helped maintain composition and abundance better than less retention, and overall the variety of treatments maintained all species. For maintaining richness, similarity, and diversity, the 15%A and 40%D treatments were transitional between the A treatments ≥40% retention, where these community parameters were maintained, and 15%D, which did not maintain natural diversity or species persistence.
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