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Redding, CA, United States

Rogers K.H.,Wildlife Investigations Laboratory | Mete A.,University of California at Davis | McMillin S.,Wildlife Investigations Laboratory | Shinn R.,01 Locust Street
Journal of Wildlife Diseases | Year: 2016

A hatch-year Swainson’s Hawk (Buteo swainsoni) recovered from Modoc County, California, US, on 12 August 2012 had malformations of the rear limbs consisting of bilateral polymelia and syndactyly. We describe the malformations and evaluate potential causes. Postmortem examination revealed varus rotation of both femurs and abnormal appendages originating from the distal medial surface of the tibiotarsi with two nonfunctional digits on the right leg and one digit on the left leg. There was syndactyly between digits III and IV of both feet. Avian pox viral dermatitis was present on the skin of the ventral abdomen. A definitive cause of the skeletal malformations was not identified. © Wildlife Disease Association 2016. Source


Furnas B.J.,01 Locust Street | Callas R.L.,724 Ball Mountain Road
Journal of Wildlife Management | Year: 2015

Automated recorders and occupancy models can be used together to monitor population trends of multiple avian species across a large geographic region. Automated recorders are an attractive method for monitoring birds, because they leave a record that can be independently validated and multiple units can be programmed to repeatedly survey different locations at the same daily times. We assessed the use of automated recorders and single-species, single-season occupancy models to monitor common forest birds across a 5.4-million-ha region of northern California. Using a survey protocol of 5-minute recordings at 3 times of the morning repeated over 3 consecutive days at 453 sites, we detected 32 species at >10% of these sites. Five of these species (Steller's jay [Cyanocitta stelleri], mountain chickadee [Poecile gambeli], red-breasted nuthatch [Sitta canadensis], dark-eyed junco [Junco hyemalis], and western tanager [Piranga ludoviciana]) were dominant with occupancies >0.5. We also modeled occupancy associations with elevation and canopy cover for brown creeper (Certhia americana), MacGillivray's warbler (Geothlypis tolmiei), and western tanager and found the environmental conditions at which occupancy was maximized differed by up to 399m in elevation and 17.9% canopy cover for these species. Given a sampling effort of 100 new sites per year, we demonstrated 80% power (α=0.1) to detect occupancy declines as small as 2.5% per year over 20 years for the 32 most common species. The effective radius of automated recorder surveys was approximately 50m. In a field test, surveys conducted concurrently using automated recorders and point counts yielded similar occupancy estimates despite differences in detection probability. Our results suggest that automated recorders, used alone or in conjunction with point counts, can provide a practical means of monitoring common forest birds across a large geographic area. © 2014 The Wildlife Society. Source


Sweitzer R.A.,Great Basin | Furnas B.J.,01 Locust Street | Barrett R.H.,University of California at Berkeley | Purcell K.L.,U.S. Department of Agriculture | Thompson C.M.,U.S. Department of Agriculture
Forest Ecology and Management | Year: 2016

Fire suppression and logging have contributed to major changes in California's Sierra Nevada forests. Strategically placed landscape treatments (SPLATS) are being used to reduce density of trees, shrubs, and surface fuels to limit wildfire intensity and spread, but may negatively impact fishers (Pekania pennanti). We used camera traps to survey for fishers among 1-km2 grid cells of forest habitat in the Sierra National Forest, California. We used single-season (n=894 cells) and multi-season (n=361 cells) occupancy modeling to evaluate responses of fishers to fuel reduction in the 5years prior to camera surveys. We also assessed occupancy in relation to burn history, elevation, and an index of canopy cover. Camera traps detected fishers most often between 1380m and 1970m elevation, and fisher occupancy was maximized at 0.80 at 1640m elevation. Probability of detection was higher after initial fisher detection, in habitats with high canopy cover, and when surveys were done in fall to spring. Fisher occupancy was positively linked to canopy cover, and trended lower among cells with higher levels of managed burning or forest fires within 25years of surveys, and in cells where 5years of cumulative disturbance from restorative fuel reduction was higher. Local persistence declined 24% in areas with more restorative fuel reduction (0-100% of a cell), but was not diminished by prior burning, or disturbance from extractive activities (tree removals for commerce or hazard mitigation). Reduced local persistence by fishers in areas with extensive restorative fuel reduction was likely temporary; evidence from other sources intimated that they would resume higher use within a few years of ecological recovery. The trend for lower occupancy in extensively burned forest cells suggested that forest fires reduced but did not eliminate foraging opportunities for fishers. We also found that wildfires increased in frequency in our study area after the 1980s, and recent fires may increasingly impinge on higher elevation forests with higher fisher occupancy. Forest fuel reduction likely imposes a more limited short term cost to fisher habitat use than previously believed, but less is known about the responses of resting or denning fishers to management disturbance. Fuel reduction treatments could be intensified below ~1450 m elevation, which may reduce spread of fires into higher elevation forests where fishers are more common, and where denning is focused. © 2015. Source


Hendricks S.A.,University of California at Los Angeles | Hendricks S.A.,University of Idaho | Sesink Clee P.R.,Drexel University | Harrigan R.J.,University of California at Los Angeles | And 5 more authors.
Biological Conservation | Year: 2016

Reintroduction is often the only remaining option for recovery of extirpated species. According to the U.S. Endangered Species Act, species should be reintroduced to suitable habitats within their probable historical range. However, accurately defining historical range often proves difficult, especially for taxa with limited historical information, and may represent a significant impediment for successful recovery. Here, we combine ecological modeling methods with morphometric and phylogenetic data from museum specimens to define a more biologically realistic historical distribution. We apply this approach to the Mexican wolf (Canis lupus baileyi), the most endangered and genetically distinct wolf subspecies in the New World. Our model substantially increases the potential geographic range of the Mexican wolf to include areas in southern California and Baja California, areas not previously recognized as part of the historical range. Motivated by this prediction, we reanalyzed morphometric data and genetically typed the only historical specimen known from southern California, which was previously assigned to another wolf subspecies. We found that the specimen was in fact of pure Mexican wolf ancestry and fell within our predicted range for this subspecies. Our findings provide an impetus for reconsidering reintroduction sites for the Mexican wolf and highlight how critical taxonomic assignment can be to reintroduction programs and species recovery. Re-analysis of potential range in other extirpated species that have ranges defined by antiquated taxonomic approaches used on a limited number of specimens could enhance the success of future reintroduction programs and restore historical processes such as admixture that can preserve the adaptive legacy of endangered species. © 2015 Elsevier B.V. Source


Hendricks S.A.,University of California at Los Angeles | Charruau P.C.,University of California at Los Angeles | Pollinger J.P.,University of California at Los Angeles | Callas R.,01 Locust Street | And 2 more authors.
Conservation Genetics | Year: 2015

Given the recent re-colonization of gray wolves (Canis lupus) to the Pacific northwest, USA, and subsequent migration into northern California, understanding how well natural migration has restored historic diversity can inform management decisions. In this study, we report the mitochondrial DNA control region haplotypes of nine museum specimens that curators identified as C. lupus from Oregon, Nevada, and California. Among the nine samples currently available for genetic analysis of historic genetic diversity of C. l. spp. in the U.S. Pacific states, we found six previously described haplotypes including two domestic dog (C. l. familiaris) haplotypes. Notably, we present the first evidence of Mexican wolf (C. l. baileyi) ancestry in southern California while the northern Californian specimen, as well as one individual from Nevada, present a haplotype common to wolves from the historic American West and extant Canadian wolf populations. Finally, the three Oregon specimens shared a haplotype that is only observed in extant wolves from coastal British Columbia (the “coastal rainforest” wolf ecotype), indicating that the historical range of this haplotype reached as far south as southwestern Oregon. In conclusion, our results indicate that the genetic composition of historic wolf populations in the Pacific northwest and southwest states was polyphyletic and included wolves that share maternal ancestry with current populations from adjacent regions. These findings, in addition with future nuclear analyses, reveal more accurate historic range delimitations, which is critical information when designing appropriate management plans for wolves naturally re-colonizing the U.S. Pacific northwest and southwest regions. © 2014, Springer Science+Business Media Dordrecht. Source

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