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Extensive, severe wildfires, and wildfire‐induced smoke occurred across the western and central United States since August 2020. Wildfires resulting in the loss of habitats and emission of particulate matter and volatile organic compounds pose serious threatens to wildlife and human populations, especially for avian species, the respiratory system of which are sensitive to air pollutions. At the same time, the extreme weather (e.g., snowstorms) in late summer may also impact bird migration by cutting off their food supply and promoting their migration before they were physiologically ready. In this study, we investigated the environmental drivers of massive bird die‐offs by combining socioecological earth observations data sets with citizen science observations. We employed the geographically weighted regression models to quantitatively evaluate the effects of different environmental and climatic drivers, including wildfire, air quality, extreme weather, drought, and land cover types, on the spatial pattern of migratory bird mortality across the western and central US during August‐September 2020. We found that these drivers affected the death of migratory birds in different ways, among which air quality and distance to wildfire were two major drivers. Additionally, there were more bird mortality events found in urban areas and close to wildfire in early August. However, fewer bird deaths were detected closer to wildfires in California in late August and September. Our findings highlight the important impact of extreme weather and natural disasters on bird biology, survival, and migration, which can provide significant insights into bird biodiversity, conservation, and ecosystem sustainability. Key Points: We investigated the environmental drivers of massive bird die‐offs by combining earth observations with citizen science observationsWe found distance to wildfire and air quality were the major factors that affect the birth mortality eventsOur findings highlight the important impact of extreme weather and natural disasters on bird biology, survival, and migration [ABSTRACT FROM AUTHOR]

As wind turbine‐caused mortality of birds and bats increases with increasing wind energy capacity, accurate fatality estimates are needed to assess effects, identify collision factors, and formulate mitigation. Finding a larger proportion of collision victims reduces the magnitude of adjustment for the proportion not found, thus reducing opportunities for bias. We tested detection dogs in trials of bat and small‐bird carcasses placed randomly in routine fatality monitoring at the Buena Vista and Golden Hills Wind Energy projects, California, USA, 2017. Of trial carcasses placed and confirmed available before next‐day fatality searches, dogs detected 96% of bats and 90% of small birds, whereas humans at a neighboring wind project detected 6% of bats and 30% of small birds. At Golden Hills dogs found 71 bat fatalities in 55 searches compared to 1 bat found by humans in 69 searches within the same search plots over the same season. Dog detection rates of trial carcasses remained unchanged with distance from turbine, and dogs found more fatalities than did humans at greater distances from turbines. Patterns of fatalities found by dogs within search plots indicated 20% of birds and 4–14% of bats remained undetected outside search plots at Buena Vista and Golden Hills. Dogs also increased estimates of carcass persistence by finding detection trial carcasses that the trial administrator had erroneously concluded were removed. Compared to human searches, dog searches resulted in fatality estimates up to 6.4 and 2.7 times higher for bats and small birds, respectively, along with higher relative precision and >90% lower cost per fatality detection. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society. Searching for fatalities at wind turbines, skilled scent‐detection dogs improved carcass detection rates over human searchers 17‐fold for bats and 3‐fold for birds, and in concurrent, overlapping fatality monitoring, human searchers found none of the 71 bat fatalities and 17% of the bird fatalities found by dogs. Findings of dogs increased fatality rate estimates over those of human searchers 6.4‐ and 2.7‐fold, respectively, along with higher relative precision and >90% lower cost per fatality detection. [ABSTRACT FROM AUTHOR]

Wind energy is widely recognized as a key element of the worldwide effort to limit greenhouse gas emissions. As compared with the general population, environmental activists have a much higher level of knowledge, interest, and capacity to affect the final outcome of a proposed wind turbine facility. To explore how their opinions on wind energy, particularly on vertical‐axis wind turbines, differ from the general public, we administered the same online experimental survey to a general population sample of adult Californians and to a self‐selected sample of online energy and environmental activists. We find that support for wind energy increases with the degree of environmental activism and engagement. The general public prefers vertical‐axis wind turbines in open spaces, away from one's residence. Location and price sensitivity, however, are weaker among activists. Among activists, attitudes about specific vertical‐axis wind turbine technologies are more crystalized and less susceptible to the information effects except on the topic of minimizing bird deaths. Highlights: Attitudes toward wind energy differ among environmental activists and general public.General public prefers vertical‐axis wind turbines (VAWTs) in open space, further from one's residence.Location and price sensitivity are weaker among activists.The potential of minimizing bird deaths increases support for VAWTs. [ABSTRACT FROM AUTHOR]

Objective: Marijuana (Cannabis spp.) growing operations (MGO) in California have increased substantially since the mid-1990s. One environmental side-effect of MGOs is the extensive use of anticoagulant rodenticides (AR) to prevent damage to marijuana plants caused by wild rodents. In association with a long-term demographic study, we report on an observation of brodifacoum AR exposure in a threatened species, the northern spotted owl (Strix occidentalis caurina), found freshly dead within 669-1347 m of at least seven active MGOs. Results: Liver and blood samples from the dead northern spotted owl were tested for 12 rodenticides. Brodifacoum was the only rodenticide detected in the liver (33.3-36.3 ng/g) and blood (0.48-0.54 ng/ml). Based on necropsy results, it was unclear what role brodifacoum had in the death of this bird. However, fatal AR poisoning has been previously reported in owls with relatively low levels of brodifacoum residues in the liver. One likely mechanism of AR transmission from MGOs to northern spotted owls in California is through ingestion of AR contaminated prey that frequent MGOs. The proliferation of MGOs with their use of ARs in forested landscapes used by northern spotted owls may pose an additional stressor for this threatened species. [ABSTRACT FROM AUTHOR]

The article presents a study which shows the rates of avian fatality from collision with 50 and 60 meter meteorological towers near wind turbines at the Altamont Pass and Collinsville Montezuma Hills in central California. It states that the Horned Lark, pipits and sparrows contribute to 60 percent of carcasses followed by seven percent of carcasses in night-migrating song birds. It concludes that there is no proper information on bird's fatality from towers of these height.

A bstract In Humboldt County, California, nest exclosures were used between 2001 and 2006 to reduce the predation of eggs aiding in the recovery of a threatened population segment of western snowy plovers ( Charadrius nivosus). Due to a sudden increase in adult mortality in 2006, field biologists abandoned the use of nest exclosures. This paper describes a discrete-time stochastic model designed to compare two different management strategies (with and without exclosures) to predict the change in the plover population. The model uses beta distributions to model demographic parameters, and whenever possible, these distributions were fit to survey data of these populations. The model shows nest exclosures to be effective in increasing chick fledging rates. However, the model also shows that an increase in adult mortality potentially caused by the nest exclosures would counteract this increase in fledging rates. The model predicts that there will be a net negative effect on the population if these exclosures reduce adult survival to 90% of its unexclosed rate. The model also demonstrates that the population is dependent on immigration. [ABSTRACT FROM AUTHOR]

The article presents a study on the age and sex structure of Western and Clark's grebes that were killed in three mortality events in California. The researchers chose the mortality events because of their impact on grebes and because of the availability of carcasses stored originally as evidence. They also used logistic regression analysis to test if gonad maturity indices predicted the absence or presence of bursa. They found that the potential initiation of courtship in Western and Clark's grebes during the nonbreeding season is a mechanism that may affect wintering patterns of adults.

In a recent paper, Smallwood et al. (2010) conducted a study to compare their 'novel' approach to conducting carcass removal trials with what they term the 'conventional' approach and to evaluate the effects of the different methods on estimated avian fatality at a wind power facility in California. A quick glance at Table 3 that succinctly summarizes their results and provides estimated fatality rates and 80% confidence intervals calculated using the 2 methods reveals a surprising result. The confidence intervals of all of their estimates and most of the conventional estimates extend below 0. These results imply that wind turbines may have the capacity to create live birds. But a more likely interpretation is that a serious error occurred in the calculation of either the average fatality rate or its standard error or both. Further evaluation of their methods reveals that the scientific basis for concluding that 'many estimates of scavenger removal rates prior to [their] study were likely biased low due to scavenger swamping' and 'previously reported estimates of avian fatality rates ... should be adjusted upwards' was not evident in their analysis and results. Their comparison to conventional approaches was not applicable, their statistical models were questionable, and the conclusions they drew were unsupported. © 2013 The Wildlife Society. [ABSTRACT FROM AUTHOR]