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We analyzed data on the size of nesting aggregations of Sabine's Gulls (Xema sabini) observed in the Yukon–Kuskokwim Delta (YKD), Alaska, between 1986 and 2013, to determine whether the species is a “solitary low-density nester” there, as in other parts of its range. Data for 1087 nests show that 56% of Sabine's Gull nests were solitary and that <3% of aggregations exceeded 10 nests, although factors positively correlated with the evolution of colonial nesting, including exposure of nests to predators, aquatic habitat, and absence of feeding territories, apply to Sabine's Gulls nesting in the YKD. Although Sabine's Gulls in the YKD were most often solitary nesters, in 2010 we found a 102-nest aggregation on a small island in the study area, larger than any reported for the species. Among all aggregated nests, 75.4% occurred on islands, and only 13.9% along shorelines, while 39.8% of all solitary nests occurred on islands, and 39.3% along shorelines. The proportion of Sabine's Gull nests in the YKD located on islands ranged from 0.15 (in 1991) to 0.78 (in 2010) and showed no significant trend between 1986 and 2013, despite an increase in population size during the period. Although islands may provide greater protection from mammalian predators, and the majority (54.6%) of Sabine's Gull nests in our study area occurred on islands, thousands of similar, apparently suitable islands remained unoccupied by Sabine's Gulls and other nesting species every year. Given the potential benefits of nesting on islands, in colonies, or in colonies on islands, the YKD Sabine's Gull population maintains considerable behavioral variability, in terms of nest-site selection and size of nesting aggregations, perhaps to take advantage of locally abundant food resources.
Several species of forest carnivores are of state or federal concern in Oregon and are or may be sensitive to timber management practices, wildfires, climate change, and other large-scale disturbances. We implemented a non-invasive survey of forest carnivores in the northern Cascades of Oregon during fall–spring, 2012–2014. We collected 111,148 images from 21 elevated and 39 ground-level baited camera stations located from 586 to 2237 m in elevation. We detected (≥1 image) Red Fox (Vulpes vulpes) at 9 ground stations, of which 4 also detected Coyote (Canis latrans). We detected American Marten (Martes americana) at 63% of all stations (elevation range = 1252–2237 m), including 5 of 7 stations located in areas that experienced wildfires since 1996 that covered >5000 ha. Other forest carnivores detected included Bobcat (Lynx rufus), Black Bear (Ursus americanus), Mountain Lion (Puma concolor), Northern Raccoon (Procyon lotor), American Mink (Neovison vison), weasel (Mustela spp.), and skunk (Mephitis mephitis, Spilogale gracilis); but we did not detect Wolverine (Gulo gulo), Canada Lynx (Lynx canadensis), Fisher (Martes pennanti), or Gray Wolf (Canis lupus). Future periodic non-invasive surveys of forest carnivores may provide information about changing species composition and distribution, especially in relation to climate change, vegetation succession, and potential recolonization by Gray Wolves.
Alvord Chub are small minnows endemic to the Alvord Basin, a endorheic desert basin in southeastern Oregon and northwestern Nevada. Comprehensive distribution surveys were last conducted 30 y ago. Recent, limited surveys raised concern that the range and abundance of Alvord Chub may have contracted. We conducted a comprehensive survey at historically occupied locations in 2013 and obtained mark-recapture population estimates. Despite 2 y of below average precipitation, Alvord Chub were present at the majority of historically occupied drainages, were abundant at many locations, but were restricted in distribution in several drainages. Additionally, we documented current threats, which included water withdrawals, nonnative fishes, grazing, habitat fragmentation, and desiccation. Based on our observations, we suggest a number of management recommendations.
Deep-sea anglerfishes were taken in trawls between 1999 and 2006. The 3 most commonly encountered species, Oneirodes thompsoni, O. bulbosus and Chaenophryne melanorhabdus, were known already from British Columbia waters, and here we report significant range extensions for these 3 species. Ceratias holboelli also had been reported from British Columbia, but until now, no specific collection localities had been published. In addition, 3 oneirodids (Oneirodes eschrichtii, O. acanthias and Chaenophryne longiceps), Melanocetus johnsonii (Melanocetidae), and Cryptopsaras couesii (Ceratiidae) are reported for the 1st time from British Columbia.
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